How to Sculpt a Cake - Into Anything!

This instructable will lay out some details of the basic planning & execution steps to take when making a sculpted cake. For almost any desired sculpture you can turn it into a cake, with the same few steps, just by slightly modifying the process as you go and making some key decisions along the way. For this instructable I will use examples from my tree stump cake and my battleship cake, which you can follow along with if you want to make those specific cakes. It's a long instructable and a rather difficult process - you have been warned! - but it is very rewarding at the end. Clearly I'm not a professional - but you don't need to be to make an impressive cake to make any event or occasion to the next level.

General supplies:

1. Cake – ingredients, mix, standard baking utensils; this is not an instructable that teaches you how to bake a cake, it teaches you how to sculpt one.
2. Icing - fondant (store-bought), and buttercream ingredients
3. Ruler
4. Foam board
5. A nice sharp kitchen knife
6. Stanley knife
7. Pens, pencils, paper, erasers
8. Tin foil
9. Baking paper
10. Plastic straws (this is a tough one to find – wooden chopsticks can be used as an alternative)
11. Rolling pin
12. icing sugar
13. Food dyes / food colouring – green, brown, black, yellow, red for the stump cake
14. A big platter or a sheet of plywood
15. Paintbrush
16. cup of water and plate

You will also need desiccated coconut for the stump cake, and sparklers and Pocky sticks for the guns and mast of the battleship.

This part is REALLY IMPORTANT – if you have done this many times before, you might know what you are looking for but if it’s the first time you need to do your research on what type of cake to make. The basic requirements for your recipe are for it to be firm – it needs to hold up its own weight, but still be soft enough to taste like yummy cake. There are two options here:

a) Buy a cake mix. If you have a nearby cake decorating shop, there is no harm in just buying the mix and using it, It will almost certainly come out perfectly

b) Go from scratch. This is an equally valid option, albeit a more difficult and risky one. However it will be much cheaper! And it leaves you options for making variations (eg chocolate, coffee, caramel flavoured cake, marbling, or even vegetarian or vegan options)

If you have chosen a), go directly to step 3. If you have chosen b) (good choice!) then you have to do your own research to find a good recipe, but one rule of thumb is to get a cake with lots of eggs. These provide a spongy, solid structure to the cake and make it very firm. Searching for cake sculpting recipes would be the best idea, and look for ones with nice photos or even videos which show you what the final product looks like.

I recommend this recipe as a starting point - however it is more mid-range in terms of tasting good vs being sturdy, so if you are attempting something more ambitious, try to find something denser. This one would work for the stump cake, but maybe not so well for the battleship.

For my stump cake, it had to be fully vegan - meaning no eggs allowed in the cake recipe! This made it extremely difficult, especially to make the books that went on top, as the cake was soft and crumbly. Bear this in mind when you design your cake - you will be limited by the properties of your cake. That's why the next step is crucial!

This will give you a chance to mess it up once and iron out any problems with the recipe you choose to follow, and make sure the cake will have the properties you need it to. If all goes well, you can just use the test cake as the real one, or as a backup!

Take this time to also take inventory of the baking equipment you have available, as this will be an important factor in how you plan to construct your cake later.

Unless you already have a model of the thing you want to cakeify, you will have to come up with your own way to visualise it. For me, the most effective way to do this is to create a digital model of it before I start so that I can have an easy reference. It also acts as a sort of first run through so you don't have to think too much about creative decisions while you actually make the cake, because you have already made them while making your model. You can construct a model in a variety of different ways.

If you are copying something that already exists in real life then you are off the hook a bit here because you may already have exactly what you need to copy on hand. However if you are constructing something from your imagination or from limited photos (these were the only photos I had of the battleship), you will need to get these in one place. Create a folder on your desktop which you can put all relevant information about the cake at this point - there will be a fair amount of things that you will need to put in there.

For me, I always like doing the extra bit of work to make either a CAD (computer assisted design) model (for sculptures that are rigid and geometric and require precise measurement), or a digital sculpt (for organic models that I have in my head and want to bring to life). If you have never done either of these things before, it will take a while to get used to; you can skip this step if you are in a pinch, but it will really help if you take the time to learn. For CAD, you can use free software like Sketchup, Blender, of my personal favourite, DesignSpark Mechanical. For the battleship model, I had only two blurry photos to work from, and I simply had to do my best to make an accurate model from the photo. For this cake, I could not have done it without the CAD model because it gave me all the measurements I need. CAD is very intuitive on a basic level, and you will quickly get the hang of it if you give it a try. Go to the DesignSpark Mechanical website and you can get started in only a few minutes.

For organic structures where you want to be more artsy, the digital sculpt is optional, but it can be very useful to help put 3D substance into your idea. It’s basically an easier version of sketching what you want to make (though I do recommend that as well, to start you off). You can use Zbrush core mini (free) or Sculptris (also free) or any other sculpting software you can get your hands on. They are all really the same for this purpose, and again, they are quite intuitive for basic things. Everyone thinks they know what a tree trunk looks like - but to turn it into a cake it can be really helpful to have a model as a target for the final aesthetic that you are going for.

You can make almost any sculpture into a cake – however there are certain limitations that mostly depend on the limits of your resources, time, and creativity. I will try to address these in later steps.

You can do this digitally or by hand; the goal of this step is to mark out all relevant measurements so that you have a reference point. Notice that the units for the battleship measurements are very small - this can simply be fixed later, for example if I used cm instead of mm.

It is important to include overall measurements of the dimensions. These do not have to be correct - the point of this step is to measure the proportions of each part of the model relative to itself. If your measurement of the overall length is 50cm, but you only want to make a 25cm cake, you can just halve all the measurements you took to make your final model.

You need to know how big your cake needs to be. The easiest sculpts will happen when the longest edge of your sculpture is smaller than the largest pan you have. This will let you slice your sculpture (mentally or physically in your sculpting software) into cross-sectional layers which you can then just stick on top of each other one by one to build your cake from the base up.

That is the fundamental way to build a cake – cutting layers and stacking them. If the cake is too big, you can always partition the layers you need into two or even three (if you want to push it) pieces which can be collaged into a cohesive layer. More on that later.

To plan out the pieces, imagine you are building a solid block which has the approximate shape of your final sculpture, but is too big. This will allow you to actually cut down that block and sculpt it into your final shape. Remember – it’s a lot easier to cut away more cake than it is to add more.

If your sculpture isn’t so convenient, or crucially if it is too tall, you are going to need some help constructing it. Unfortunately, even the sturdiest cake will not support significant overhangs or thin sections, so if your design requires those things, you can enlist cake boards, plastic sheets, or any other sheet of anything food-safe that wont bend. For me, I like foam board, often called foam core in some places. Cut out a piece of this that is the same shape as your cake piece, wrap it in foil, and you are ready to go with a custom-purpose board. You can then cut some straws to length and poke them through the cake so they just stick out of the top, and they can support the weight of the foamboard and everything on top of it. For example, if you wanted to make a mushroom, it would be easy - or even a house ON a mushroom! This one would be tougher – notice the straws in the bottom layer are more widely spaced than the ones on top. That’s because the whole cake is essentially balanced on itself – you have to be very mindful of the centre of gravity of your cake. There are ways around it to make asymmetrical overhangs etc, but they are all complex and ambitious so I wont cover them here as this technique will suffice for the majority of cakes.

Notice how the fondant can be built up thick enough to conceal the edges of the board at the base of the house; there are plenty of ways to conceal the boards in the final cake, so don't worry about them being visible at the end.

The cake board technique will also be important for very tall cakes. If you just keep stacking cakes on top of one another, eventually the weight will build up enough that the cakes at the bottom will start collapsing in on themselves and your whole creation will take a tumble. Periodically placing cake boards will stop this from happening by redirecting the weight of the cake into the supports and finally into whatever sturdy surface you assemble the cake on.

For simple cakes, this will be a simple task, as the image in step 7 shows. You need to partition your model into sections that you can cut out of a cake and then reassemble into your final model. For something like the battleship which is more complex, you can section your model into simple shapes and then figure out how large they are using the measurements you took for your blueprint (step 6).

It can help to partition your model into sections; for example, the battleship was very long, so I ended up using 3 pieces for the base. You can also get creative with the cake you have available - for the middle layer of the stump cake, I used 3 blocks of cake tessellated together that were left over from my test cakes (I did chocolate and vanilla). Keep in mind that this will greatly decrease the structural integrity of your final cake - so if the layer will be supporting significant weight, it's best to avoid this strategy. We can still use the leftover cake for other stuff - more on that in steps 15-17.

Once you have planned out both the cake pieces and the cake board structure, either print out to scale or draw out on paper the shapes of the cake pieces, and draw out the cake board shapes onto the foamboard. Cut out the foam board pieces with a stanley or craft knife, and cut the paper shapes out too – you’ll need them for step 14. Figure out how much cake you will need to successfully fit in all the paper pieces and still have leftover cake. You can do this visually – just try to tesselate the paper templates as best you can, and if you cant fit them all on one cake, you’ll have to bake two.

If you are doing the tree stump or something else that is organic and not structurally complex, this step is not technically required but you will always get a better result if you make proper templates than if you wing it.

The images here are the pieces of the battleship cake. I made them in 3D to check that they would all fit inside the cake vertically as well as horizontally, and then made a 2D version to cut out and stick on top of the cake (I have a very big rectangular cake pan, but this would also work with multiple smaller tins).

Use the recipe you chose and tested in step one to make however much cake you need to cut out all pieces with some to spare. If you need to make multiple cakes to achieve this, feel free to do it a couple of days in advance so that by the time you get to assembly day, all your raw materials (ie the cake) are ready to go.

The first thing in your assembly is figuring out a base. You don’t have to build the cake on the thing you will serve it on, but whatever you do build it on, it’s not coming off – you’ll have to transfer the base onto the platter you serve on. If you are doing a really big cake, chances are you won’t have a big enough platter to fit the cake on. In this scenario the best option is to cut out an appropriately sized piece of ¾” (~1.8cm) or ½” (~1.2cm) plywood, clean it and wrap it in foil. If you are going to do the construction over multiple days (you might well need to!) or have limited working space, you might want to build the cake on a smaller, portable base so you can keep it moving around, or even fit it in the fridge overnight. Keep in mind that you only need to refrigerate the cake if it is unsealed – ie straight cake or with buttercream icing. Once it is wrapped in fondant icing you should NOT refrigerate the cake as it is sealed and can simply be wrapped in cling wrap or even left under a tea towel and it will not spoil.

For the stump cake I used a piece of foamboard, cut to the shape of the bottom of the stump and wrapped in foil. This let me move it around whenever I needed.

Once you have chosen your base, the next step is to prepare your buttercream. Have an excess of this stuff – it's going to come in handy. You want a thick buttercream recipe – its sort of going to be a structural element in itself, so you don’t want it squeezing out of cracks. Don’t stress about it though – most buttercream recipes you find online will work perfectly. Here’s one I used for the stump cake.

Think about what colour you want your buttercream to be; usually it wont be visible, but in case any leaks through the outer layers of decoration, make it a colour that will blend in. For the books that went on top of my tree stump, I made the mistake of using chocolate buttercream underneath white fondant, and it leaked out of a couple of seams, and was pretty much impossible to hide after that as it stained the white fondant. Pick a colour, or multiple if necessary, and divide your buttercream up and add whatever colouring you want.

Make sure the cake is approximately flat; you can use a breadknife to cut off any dome or cracks that formed during the baking process. KEEP THESE OFFCUTS – you might need them. Once your cakes are planarized, lay out your templates from step three and cut around them to make your pieces.

Take your base and put down a layer of buttercream, then stick down the bottom cake layer on top of it. Put down another layer of buttercream on top. If you need to reinforce, stick your straws down into the cake (through the buttercream) and cut them so they are flush with the surface of the cream. Repeat this for every piece of cake and every cake board, so you are left with a series of cakes on boards with buttercream on top so that you can stack them all together. Then just put them on top of each other!

Sculpt away! Cut down your block until it more vaguely resembles your shape. Cut away little bits at a time, like whittling, until you are satisfied that you are as close as you can get to having the right structure.

This is what you saved all your offcuts for. Using spare cake pieces, you can stick on extra bits of cake with buttercream to bridge larger spaces, and the best part – roughly mash your spare cake in with some buttercream to make a cake-pop-like cement that you can wedge into any nooks and crannies to fill them up. Between these two techniques you should be able to arrive at both a sturdy and smooth rendition of your original design. You may opt to chill your cake for a while after this step to let everything settle and set before the next step – the crumb coat.

This is simply applying a layer of buttercream over the whole cake (every bit of it!) and scraping it down so that you are left with a thin layer of buttercream that has seeped into the outer pores of the cake and sealed in all the stray crumbs. You should now chill your cake thoroughly. The time this will take will depend on how big the cake is, but there is no upper limit. Leaving it in the fridge for a while or even overnight is fine.

Fondant is a type of pliable, sugar-based icing clay that can be used to give beautiful matte finishes on cake. It can also be coloured and sculpted into a variety of different forms. It is the stuff that is on traditional wedding cakes - but dont confuse it with marzipan. You can get fondant at most supermarkets, though it might be advertised as "kneadable icing" or "ready to roll" or "sugarpaste" in the UK.

The fondant is the thing that will really transform your cake, and the first thing to do is to prepare your fondant colours, while your cake is still in the fridge. Once the cake comes out of the fridge, you can’t put it back in as the fondant will become moist and lose that professional-looking matte finish. Colouring your fondant is as simple as choosing a colour (or a mix – above is an easy colour chart for Queens food colouring) and putting a few drops into your lump of fondant, then kneading it through. Place the dots of food colouring in the centre and seal them in so they don’t leak out, then begin the process of stretching and folding the fondant to incorporate the colour through. If your fondant begins to stick to your work surface, use icing sugar or corn starch to keep the outside dry and workable. Do be careful of adding too much; it can dry out the overall block of fondant.

You will notice that if you roll the fondant out into a tube, then fold it on itself and repeat, you can get a particular marbling effect where the colour streaks through the fondant. You can take advantage of this; for example, wood, roll out a strip of dark brown fondant and one of light brown fondant, and lay them together. Fold the combined strip on itself and roll it out to the same thickness as it was before. After repeating a few times, you will see that there are streaks of dark and light brown that resemble the grain of wood. You can then take this and curl it into a snail on a piece of baking paper, put another piece of baking paper on top, then roll out the whole thing with a rolling pin. This will give you a disk of fondant that resembles the marbling and rings on an old tree! There are many other applications of the technique however, and really any surface can be made more interesting with some well-thought-out marbling of similar colours.

In general, a layer of fondant should be ~1/8 inch, but going a little thicker is safer. Don't stress if your fondant is thick - it's also delicious.

In general, you may be able to just roll out a large piece of fondant and drape it over the top of your cake. There are plenty of online tutorials about applying fondant; if you feel uncertain about this step, have a look on YouTube.

For more geometric shapes, you may have to be more strategic to get things to work. If you remember nets from middle school geometry - the 2D unfolding of a 3D shape - you can cut them out of fondant and use them to encase different objects. For the books that went on top of my tree stump cake, I used two different shaped and coloured rectangles of fondant to encase rectangular prisms of cake, ands then scored the sides with a knife to resemble paper.

For this cake, we then roll out the fondant disk onto the top. You can do this by wrapping it around your rolling pin, then unfurling it onto the surface of the cake. Trim the edges a little and cut some lines with a sharp knife going towards the centre of the trunk – these resemble cracks in dried wood. You can push the cuts open a little; the chocolate buttercream below will be dark enough to look like a convincing crack as long as it isn’t too wide. if the edges need trimming, trim them to be approximately flush with the walls of the trunk.

With a darker brown fondant, roll out approximately rectangular pieces of fondant at the approximate height of the cake and stick them on the sides, squishing the pieces together at any junctions. Its ok if they overlap a bit; this will be rough bark, so It isn’t expected to be uniform.

You can do to fondant pretty much whatever you can do to clay - so get creative with it!

For the bark on the tree stump: with the back side of a knife, you can gently pinch and furrow the fondant to create a rough bark texture. Don’t be too rough, or you could split the fondant. If any splits do occur, try to wipe away any buttercream that leaks out and patch the gap with a bit of fondant.

For this cake, I wanted a sense of new life; I made some little mushrooms with more fondant and just stuck them to the cake. Give this a try; you will quickly get a sense of the limitations of the fondant. For the plate mushrooms, you can also rough up the back of the mushrooms and wet them; this will help them stick to the bark better.

In general, fondant gets softer the warmer it gets, and remember that you CAN'T PUT IT IN THE FRIDGE (I forgot this for my stump cake and left it in the fridge overnight - that's why it looks a bit glossy and weird in the cover photo). So the range of options you have for making little fondant sculptures is in some ways dependant on your climate. If the cake will be in a warm area, stems and overhangs will droop significantly. You can use other things as decoration here too - biscuits, chocolate pieces, modelling chocolate, lollies etc - simply browsing the supermarket is sometimes enough inspiration to figure out a new edible way of representing something. You can reinforce a fondant sculpture with Pocky sticks, for example, if you wanted to make a branch coming outwards from the stump. Keep in mind that the next step is painting - you might want to delay putting some decorations on until after that step. The image above was taken after painting as I did not want to accidentally paint over the moss, which I made by mixing some diluted green food colouring with some desiccated coconut.

For the battleship, I used pliers to cut lengths of sparklers and used them as the barrels of the cannons; when we brought the cake out, we lit all of the guns at the same time.

You can dilute food colouring either with water of vanilla essence to form a wash or paint to add detail to your sculpture. The alcohol content of vanilla essence makes it more suitable as it evaporates and leaves a matte finish, whereas water may leave a slightly more glossy finish. Vanilla extract is usually brown however so it may not be usable for lighter food colouring. Once you have made your dilute solution, you can use a paintbrush to deepen shadows or tint your cake; particularly for the bark, a very dark brown or even black dilute wash painted into the cracks of the bark can really help add an extra element of depth to the surface. You can also use more concentrated colouring as ink to paint or write with. Food-safe transfers can also be useful here, but a steady hand is the more versatile option! The book covers and spine were painted on by hand with a fine brush.

For the stump cake, I had to put the stack of books on top of the trunk. Since I was concerned about the weight concentrated in the centre, I opted to build a skeleton that supported the bottom of the books with straws that ran through the log. This meant that the books were built on a cake board so that I could move them around. To conceal the board when I put the books on the stump, I cut out a measured rectangle from the fondant on top and lowered the board into the cavity so that the bottom of the boos, rather than the bottom of the board, was flush with the tree stump surface. This is similar to the mushroom-house diagram from step 8.

It can really boost the aesthetic of your cake if you decorate your board/platter around the base of your cake. This can make it look like the cake is more organically rising out of the surface, or put it in an environment. You can generally achieve this with some strategic buttercream spreading and texturing; for my stump cake, I wanted to lay down a thin layer of chocolate buttercream (like dirt) and put more green coconut on top to look like grass or more moss, however in the end I ran out of buttercream so I could only do this a little bit. For my battleship cake I just ran out of time! It's not an essential touch, but it definitely helps.

The final product is above! Hopefully if you followed this not-so-short instructable you will have your own rendition, or even better, a unique cake that you designed and made yourself!