The Very Hungry Caterpillar is a great theme for a child’s first birthday. Apart from being an old family favourite, it’s gender neutral, age appropriate and a really easy theme to implement: the multi-colours and variety of food give you loads of scope for creating a bright and colourful setting with a balance of healthy food and party favourites.

For Albie’s party I made a 6 layer rainbow cake decorated with buttercream, fondant icing and sugar paste food shapes.

I used 7” tins, to make cakes with a 1.5cm depth (after trimming). You could also use 6” tins for a taller cake or larger tins for thinner layers. For me personally, I wouldn’t go any bigger than 1.5cm layers – after you’ve assembled the cake with buttercream, plus the final 2 -3 layers of icing and decorations your cake ends up pretty big!

I made the cakes the evening before the party, wrapped them in cling film and stored them in the fridge overnight. You can also freeze the cakes as soon as they have cooled and they will stay fresh. You will then need to let them defrost in the fridge overnight before assembling your cake. Cold cakes are also better when it comes to decorating.


For the cake:

  • 350g self-raising flour
  • 350g unsalted butter at room temperature
  • 350g caster sugar
  • 6 medium eggs
  • 3tsp baking powder
  • 1 tbsp vanilla extract

For the buttercream:

  • 600g icing sugar sifted
  • 100g butter at room temperature
  • 250g full fat cream cheese at room temperature


Pre-heat the oven to 170 degrees/gas mark 4

Line the base of your tins with baking paper and grease the edges of the tins with butter.

Sift the flour and set aside.

To mix the cake batter I used an electric hand mixer, but you can also mix by hand. Cream together the butter and sugar for a few minutes until it is light and fluffy. Then turn the mixer speed down and add the eggs and flour a little at a time. Finally add the baking powder and vanilla extract.

Divide your mixture evenly between 6 bowls. I used a large spoon utensil and guessed at the initial amounts and then weighed each bowl, topping up the lighter ones with the remaining batter.





Then for the fun part – the colouring! Start by adding a little bit of the gel paste, around half a teaspoon and keep mixing and adding until you’re happy with the colour. Don’t be fooled into thinking that each colour will require the same amount (if your first colour takes, say a teaspoon). Some of the pastes are surprisingly bold and I found that yellow and purple needed around half the amount of the others.

Pour your cake mixture evenly into the tins and bake in the centre of the oven for 20 minutes, or until a skewer comes out clean. If you find that your cakes are domed then move them down to a cooler part of the oven so that they cook more evenly.

Leave the cakes to cool in the tins for 10 minutes and then tip out onto a wire rack to cool completely before wrapping in cling film and storing in the fridge.


Bring on the buttercream!

It can be easy to get it wrong with buttercream so you this isn’t one that I’ve found you can throw together with little thought! Your butter and cream cheese both need to be full fat. Reduced versions of either can produce curdled buttercream because the fat is needed to stabilise the buttercream.


They both also need to be at room temperature (16-18 degrees). If the two ingredients aren’t at the same temperature the emulsion of fat and liquid can separate giving you a cottage cheese like texture. It’s also worth checking that your mixing bowl isn’t too hot or cold. 

If your butter is too cold you’ll need to whisk it first to soften it and too much whisking can give you air bubbles. Also, if your butter is too firm or your icing sugar is not sifted, you can end up with lumpy buttercream from the ingredients not mixing together properly.

I prefer to mix my buttercream by hand so that I can keep a close eye on it, but if you use an electric mixer it needs to be on a slow to medium speed. Once your buttercream is smooth and all the ingredients are combined – stop. You can overbeat it and end up with a runny buttercream if you go too fast for too long. If everything is getting a little bit too hot and runny you can chill it and then bring it out of the fridge to gently come back to room temperature.


Assembling your cake

Trim your cakes to ensure that the top and bottom are completely flat, this is really important to prevent your cake from leaning.


I use a rotating icing turnable for assembling and decorating cakes as it makes life so much easier – start by placing a dollop of buttercream in the centre of your cake stand or turntable and position the first cake centrally and upside down. This is especially important if you have trimmed the top of your cakes as the smoother surface will be on the underside – so ideally you want this on top as is makes applying the buttercream easier (no crumbs). 

Apply an even layer of buttercream, not too thick or your cake will be unstable and it will squish out of the sides and then continue to add your layers of cake and buttercream. Keep checking that everything is level so that you don’t end up with a wobbly cake.

Decorating your cake

Step 1: Buttercream

Once your layers are in place apply a thin layer of buttercream – this is called the “crumb coat” – to the entire cake. At this stage you can fill in any gaps between your layers of cake. The crumb coat doesn’t have to be perfect as you will add another layer later so don’t worry if there are crumbs and imperfections, then pop it back into the fridge for an hour.


You can then add your second layer of buttercream and it’s worth spending the time to make sure that this layer is as perfect as possible – you will still apply your fondant icing over the top but the final layer of buttercream determines the finish of your cake overall.

Once everything is as even as possible dip your spatula into a jug of boiling water and smooth over the entire surface of the cake before chilling again.

Buttercream makes a great topper and you might decide to stop here and add a fancy candle or some coloured cake sprinkles.

For this particular cake I planned to use fondant decorations in bright primary colours and wanted them to pop against a bright white background so I used ready white to roll fondant paste.


Step 2: Fondant Icing

This can give a really professional finish and if you’re using fondant decorations you can also hide any imperfections with your toppers…


Start by sprinkling your work surface with some icing sugar so that the icing doesn’t stick, then knead the fondant paste with your hands to soften it. It needs to be soft and malleable and you can then roll it out into a large flat layer of icing. 

When rolling out your icing always be sure to roll forwards and backwards  – not side to side, so rotate your icing and not your rolling pin. This helps to ensure that you apply the same pressure when rolling so that your icing is the same thickness all over. To pick up your icing fold it over your rolling pin and lift the whole lot up, rather than using your hands.

Once the icing is around 5mm thick you’re ready to apply it to your cake. Again, roll it around your rolling pin to do this, lift it up and drape it loosely over your chilled cake. 

You then basically use your hands to smooth the fondant icing over your cake starting with the top. For the sides gently lift the icing up and smooth down from the top of your cake to the bottom and side to side, gently lifting and smoothing all the way around until the icing is flat against your cake with no folds or creases.To get a really smooth finish I use a fondant smoothing tool but you can get a good enough finish with smooth hands.

Finally, trim the edges at the base of your cake with a sharp knife and finish off with a ribbon, some piped icing or decorations.


Step 3: Cake Toppers

Making the cake toppers from ready to roll fondant icing can be a ton of fun as this part really is like playing with play doh and as long as you store them flat and in a cool dark place they can be made quite far in advance, whenever you have the time.


You can buy clear fondant glue to apply them to your cake but I’ve found that it’s not great in a warm environment or if the cake toppers are heavy or you are using coloured decorations on a white base because the colour runs. The absolute best way to apply large colourful decorations to a white cake is with Silver Spoon Royal Icing. Simply mix it with water to form a thick paste – almost to the point of setting – and then apply it to your decorations before holding them in place until the icing sets.

As I needed my decorations to bend around the cake I warmed them up with a hairdryer to soften them before pressing them onto the sides of the cake.


1) To get bright vivid colours you need to use gel paste. The best one I’ve found is Wilton Icing Colour Gel Paste Rainbow colours. They come in a pack of 6 and are perfect for a vivid rainbow cake with strong colours.

I’ve used Dr Oetker gel colours in the past for a Peppa Pig rainbow birthday cake when I wanted more of a pastel rainbow – but you really can’t get the same density of colour as I wanted here.

Liquid food colouring doesn’t work at all, no matter how much you add!

2) Set aside a teaspoon of each coloured batter so that you can check the colours work together as you go along.

3) Save time by using 2 cake tins (or more if you have them).

4) For icing cakes I recommend a 10″ offset icing spatula to give the straightest edges and smoothest finish. Ideally your spatula needs to be wider than your cake.

5) For fondant icing I use a large plastic rolling pin which is completely straight (wooden rolling pins with rounded ends can make grooves in your smooth surface), and it’s a good idea to remove any jewellery at this point too