Rainbow Cake

The Rainbow Cake trend is going nowhere – and now you can use Cake Décor’s super strength, bake stable Gel Food Colours to create a rainbow cake with colours that truly pop! This recipe is for 5 layers of medium thickness, but you can split it into 6 thinner layers, or make more to make a towering cake! It’s all about how many colours you want to include!


You Will Need

For The Cake:

• Cake Decor Gel Food Colours in your choice – we used Red, Orange, Yellow, Green and Blue but they are also available in Pink, Purple and Black!

400g caster sugar

• 400g self-raising flour

•  400g butter

• 100g plain flour

• 8 medium eggs

 2 tsp vanilla

5 x grease-proof paper lined 7″ cake tins

5 x bowls


For The Icing:

1 tsp vanilla extract

3 x 250g tubs cream cheese or mascarpone

350g icing sugar

A mixing bowl

A spatula



To Make The Cake:

Step 1: Cream together the butter and caster sugar.

Step 2: Add in your eggs.

Step 3: Add in your flour.

Step 4: Add the vanilla.

Step 5: Mix altogether until smooth.

Step 6: Split the mixture evenly between your 5 bowls and start mixing one colour into each fifth of the mixture – use a 1/4 tsp to start with and build until you get the desired colour.

Step 7: Pour each bowl of mixture into a cake tin.

Step 8: Bake for 1 hour 30 minutes at 140°C in a fan assisted oven, or 160º for a non fan.

Step 9: Remove and set aside to cool.


To Make The Icing:

Step 1: Beat the vanilla and cream cheese or mascarpone until smooth.

Step 2: Sift in the icing sugar, folding in with a spatula. The more you move this the runnier it will get and the chance of splitting will increase – proceed with caution!


To Pull It Altogether:

Step 1: Place your first layer of cake on your cake board then spread a small, thin layer of icing across the top.

Step 2: Place your second layer and repeat until you have your top layer in place.

Step 3: Pop your cake in the fridge for 10-15 minutes to allow it to set a little.

Step 4: Start to layer your first outer layer of buttercream over the top and sides. This first layer is your ‘crumb-catcher’ layer to initially coat the cake, so don’t worry too much about being neat and smooth, and this layer shouldn’t be opaque either – you will be able to see some of the colour still showing through from the sponges.

Step 5: Put your cake in the fridge again to let it firm up – you can leave this for anything between 10-15 minutes and an hour, depending on how much time you have.

Step 6: Take your cake out and follow up with your final layer of buttercream – this time ensuring it is thick enough that the coverage is opaque to hide the rainbow inside, and that the finish of your buttercream is what you want your cake to look like – we smoothed the top of ours out and used a small spatula to create a pattern of vertical lines down the side – but you can do whatever you please! For an extra special finish, why not top off with our Purple Mirror Glaze and spray with our Pink and Blue Glitter Sprays ala our Galaxy Cake?


Make sure if you do make this at home that you take a picture and share it with us on our Facebook page or tag us ‘@MyCakeDecor’ on Twitter and Instagram!

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