Rainbow Cake

A Rainbow cake is such a happy cake. Children and adults go mad for this vibrant cake. It elicits the very same wonder as an actual rainbow and that is something worth celebrating. We all know and experience the effects of colour every day. The brightest of colours are reserved for the best of times – holiday drinks, beachwear, party clothes, holiday decorations etc. Can you imagine a tropical holiday without a large, colourful drink heavily laden with pineapples and mangoes or orange wedges?

It then makes perfect sense to associate the best celebrations with a Rainbow Cake.

This cake is a soft and moist vanilla cake dressed up in it’s most colourful clothes.


Tips for making a Rainbow Cake

  • Use gel colours and remember that one small drop gives you a vibrant colour. Powder colours or water-based colours may alter the consistency of your cake as a lot more product may be needed  to get the right colour.
  • If you don’t have 6 baking tins of the same size, bake half of the mixture first. It is not advisable to keep cake mixtures lying around as ingredients like bicarbonate of soda and baking powder can lose their efficacy if left standing out for too long.
  • If you only have one baking tin, make your cake batter and divide it equally into 6 bowls. Colour each portion and add the mixture a colour at a time. Once all the mixture is in the baking pan, swirl the batter with a wooden skewer. The effect is a vibrant marbled pattern that is mesmerising.
  • You can frost the cake with various icings besides vanilla buttercream. Cream cheese or whipped cream frosting would work really well here. See how to make these here.
  • Using colourful sprinkles can elevate the party mood and children love a cake with sprinkles, as do adults.
  • If you are keen on the 6 layers, freeze your layers for half an hour before you decorate the cake. Balancing and handling 6 layers of soft cake is not easy. Once the cake is firmer, it is a joy to work with.


Ingredients for cake

  • 250g softened butter
  • 1 1/2 c caster sugar
  • 2 c self-raising flour
  • 4 eggs
  • 1/2 c milk
  • 1 TB vanilla extract
  • 2 TB cornflour
  • gel colours to create the rainbow colours


  • Pre-heat oven to 180 degrees celsius.
  • Grease and line 6 X 17cm round cake pans.
  • If you only have 3 pans, make one portion of the batter (halve the cake mixture and follow the same method) Divide batter between 3 pans and once those layers have been baked, repeat the process.
  • If you only have one large pan like a 23 or 25 cm pan, prepare the cake batter as indicated in the ingredients, divide into 6 portions and colour, and then add dollops of the coloured batter into the pan and swirl with a wooden skewer.
  • To make the cake add  all the cake ingredients into a large mixing bowl and beat with an electric beater till smooth, pale and voluminous. Scrape the sides of the bowl so that all ingredients are well mixed.
  • Divide the batter  equally into 6 bowls and colour carefully, a drop at a time.
  • Once you have the right colour, add cake mixture into your baking pans.
  • If you are baking single layers of different colours, baking time will be anything from 15-25 minutes. 
  • If you are making one large cake, baking time will be 40-45 minutes.
  • Cakes are done when well risen, springy to the touch and coming away from the sides of the pan.
  • Leave out to cool for about 5 minutes before turning out onto a wire rack to completely cool.
  • Once cakes are cool, freeze layers in order to decorate.
  • If you have baked a single layer, also freeze cake and split in the centre to create 2 layers of cake; even 3 if you can cut 3 slim layers.
  • Sandwich cake layers with vanilla buttercream.
  • Decorate with sprinkles or pipe swirls of buttercream on the cake.

Vanilla Buttercream

  • 250g softened butter
  • 3 c sifted icing sugar
  • 1 TB vanilla extract
  • 3-5 TB of milk/whipping cream
  • 1/2 tsp of salt
  • gel colours to colour buttercream. (optional)
  • Beat butter with an electric beater till pale and fluffy.
  • Add icing sugar in 3 batches beating well after each addition.
  • Add salt and extract.
  • Add milk a tablespoon at a time to get a piping consistency. (soft-serve ice cream)
  • Colour buttercream into various colours if desired.


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