Layered rainbow cake

I can see a rainbow… And you can see – and eat – a rainbow too, in the form of this impressive Layered Rainbow Cake that’s sure to make a loved one’s birthday. Don’t worry, it’s easier to make than you think – with our step-by-step decorating guide, you’ll be wowing everyone with your cake decorating prowess before you can say ‘pot of gold’.

Let’s get started.

Create your base

Follow our Rainbow Layer Sponge Cake recipe for a cake as impressive on the inside as the outside.

Let your sponges cool, sandwich them together with some buttercream, and crumb coat* your assembled cake with more buttercream. Once assembled, move on to a cake turntable.

Decide which and how many colours you want to decorate your cake with. Using a ruler, measure the height of your cake and divide the number by the number of coloured strips you’d like.

Using the ruler again, mark where each strip will start and finish with a cocktail stick and use the stick to score a line around the cake, so that once you’ve finished, you have a clear template to work to.

The icing on the cake

Make enough buttercream to cover your cake, then divide it into different bowls, one for each colour of your cake, and add your food colourings. You’ll find lots of top tips on how to make and colour buttercream on our How to Make: Best-Ever Buttercream Icing blog.

Fill a piping bag with your first colour and, starting at the bottom of the cake, pipe a band of colour all around the cake up to the first mark.

Take the next colour and pipe this directly above the first band.

Repeat the process, working your way up to the top of the cake with each colour.

Next, take a cake scraper and hold it against the side of the cake with one hand and use your other hand to turn the cake turntable whilst scraping and smoothing the buttercream.

Clean the cake scraper between each turn (you don’t want the colours blending too much) and continue to scrape the sides until smooth.

Cover the top of the cake with buttercream (any colour you like) and smooth with a palette knife or cake scraper.

Finishing touches

Finally, to create the rainbow swirls on top of the cake, we used our Triple Coupler with 3 piping bags containing 3 different colours of buttercream, each with a 2D nozzle, and simply piped a loop around the top border of the cake. But you can of course decorate the top however you choose.

And now, all that’s left to do is stand back and admire your rainbow cake masterpiece.

*Not sure what crumb coating is? Don’t worry, it’s very simple. Make up some plain buttercream and, using a palette knife, coat the top and sides of your cake with a thin layer. Why? Well, this thin layer will catch any loose crumbs and create a smooth surface for your top layer of icing, resulting in a more professional finish. Extra delicious butter cream and a better looking cake – what’s not to love?