Kids Cake Ideas: Jellybean Rainbow Cake Recipe

Classic rainbow cake is iced/frosted with white buttercream and then sometimes coated with sugarpaste. I am not a sugarpaste type person. I mean I can use it and sometimes bake cakes coated with it but when you have a baby pulling out of your leg most days and a 3YO who wants your attention it’s nigh impossible to find the time to do it neatly. Here’s my recipe for Jellybean Rainbow Cake.

I baked the sponge on Tuesday and did the first layer of basic icing on the same day. Essentially it’s a victoria sponge recipe based on Delia’s classic, the key is how you colour and bake the mixture. To keep it simple I flavoured every single layer and the frosting vanilla. Trust me, if you’re under pressure for time you will need to keep it simple.

If I had 4 sandwich tins I would have been able to bake it in half the time it took me. I didn’t, I had 2. However this means that it is easier to split and colour the mixture each time. It’s also easier to ensure you organise your colours because some lead onto another etc, etc.

A classic rainbow cake would have 7 layers, this has 8. The reason being that every time I baked a batch of sponge, I baked 2. It would have been rude not to include the final layer.

This is cake is loaded with sugar. It technically serves 20, however you could get more servings out of it because a slice of cake can be halved again. The ingredients cost me approximately €17 in total which means it works out at less than €1 per slice if you’re being generous.

Because this cake is different to the norm, I’m going to write the recipe slightly differently so beware!

You need to repeat the victoria sponge process 4 times in order to come up with 8 sponge cakes.

You will need the following food colourings for the sponge: yellow, red, blue

Makes approximately 30+ portions

Ingredients (repeat x 4)

  • 110g Butter
  • 110g Caster Sugar
  • 110g Plain Flour
  • 2 Medium Free Range Eggs
  • 1 teaspoon baking powder
  • 1 teaspoon vanilla extract


  • Mixing Bowl or Stand Mixer
  • Wooden Spoon
  • Weighing Scales
  • 2 Victoria Sandwich Tins (20cm)
  • Baking Parchment (non stick)
  • Scissors
  • Butter & Flour (to grease and dust the tins)
  • Cooling Rack


  1. Preheat your (fan) oven to 170 degrees celcius.
  2. Line the base of your sandwich tins with parchment paper and use the butter and flour to grease the sides, this is very important.
  3. Cut a piece of parchment paper and weigh the flour and baking powder onto it.
  4. Weigh out the butter and sugar together and cream (beat) until light and fluffy.
  5. Add 1 egg and beat until mixed.
  6. Add the second egg and beat until well mixed. If it begins to look curdled add a spoonful of flour.
  7. Pour in the vanilla extract and mix.
  8. Pick up the baking parchment and pour the remaining flour into the mixing bowl.
  9. Beat until all the ingredients are well combined.
  10. Pour half the cake mixture into the first tin, plain no colouring.
  11. Using the yellow food colouring add 1 teaspoon and stir until your batter turns yellow.
  12. Pour the yellow batter into the other sandwich tin.
  13. Bake in the oven for 25 minutes.
  14. Wash and dry your bowl and make another batch of cake mixture.
  15. Note – you slightly need to overbake these sponges as you need them to hold better when you put them together. It’s easier as this way you don’t need cake dowels.
  16. Remove from the oven and leave to cool for 5 minutes in the tin before tipping upside down and removing the tins and then the baking parchment.
  17. Leave the oven on!
  18. Wash, dry, reline and regrease the tins.
  19. This time pour 2 teaspoons of red food colouring into all the batter.
  20. Remove half into 1 cake tin.
  21. Put a further 1 teaspoon of yellow food colouring into the second half of the batter (this gives you orange).
  22. Repeat steps 13-18 above.
  23. This time pour 2 teaspoons of blue food colouring into the batter.
  24. Remove half into 1 cake tin.
  25. Put a further 1 teaspoon of red food colouring into the batter (this gives you purple).
  26. Repeat steps 13-18 above.
  27. This time pour 1 teaspoon each of yellow and blue food colouring into the batter (this gives you green).
  28. Remove half into 1 cake tin.
  29. Pour a further 1 teaspoon of red food colouring on top. You should get a grey colour. If it is quite pale then add another teaspoon of each (red, blue and yellow) to get it darker.
  30. Repeat steps 13-16 above.

That’s it, your baking part is done. Give yourself a massive pat on the back. Keep your baked cake sections apart from one another by cutting squares of baking parchment and placing between each layer on a plate. Do this before they dry out.

To decorate, finally! Please note this is a generous quantity. You may have some frosting left over but if you do pop it into a freezer bag and freeze for another day.

Ingredients (you will make this 3 times)

  • 250g Unsalted Butter (or if a block is 254g use that)
  • 500g Icing Sugar
  • 10ml Milk (wholefat or semi-skimmed is okay)
  • 1 teaspoon vanilla extract


  • 1 large bowl (or stand mixer with whisk attachment)
  • 1 wooden spoon
  • 1 spatula or knife for spreading
  • 1 cakeboard or cakestand


  1. Whisk the butter until light and fluffy.
  2. Add the icing sugar spoon by spoon on a low setting until it is completely mixed in.
  3. Use the milk to soften the mixture if it goes into a breadcrumb consistency.
  4. Add the vanilla extract and whisk for 3 mins.
  5. Spread a spoonful of buttercream on the cakeboard or cakestand before placing your first layer. This will hold the cake in place.
  6. Use the spatula to spread a thin layer of buttercream frosting between each layer of cake.
  7. Once you have the layers in place then spread the buttercream around the side. There’s no need for it to be neat as you’ll be hiding most lumps and bumps with the jellybeans.
  8. Ice the top last.
  9. For the jellybeans I used 4 bags of Lidl own brand jellybeans. There are 13 flavours in this bag. If there were less I might have separated them and put them onto the cake in a pattern.
  10. Think of building a wall. Each line of jellybeans needs to be slightly offset from the next as this increases the structural integrity.
  11. Smear some fresh buttercream onto the spot you’re going to stick the jellybeans before you put them on. That gives you some fresh “cement”.
  12. As it’s buttercream and victoria sponge, this cake will keep for up to 4 days in a cool dry place.

Related Recipes: Spaghetti & Meatball Cake and lots more Birthday Cake ideas here.

This recipe, and more, is available on Wholesome Ireland

If you have tried this rainbow cake recipe let us know what you thought of it in the comments below

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Jill is one of the co-founders of Mykidstime and a mum of 2 girls


  1. Christine says:

    I baked it! And it turned out wonderful. Just took me about 5-6 hours! But it was well worth the effort as all the party guests really appreciated it.

  2. Well done Christine!
    I know it’s very time consuming but it is a fab result at the end. If you have any pictures you’d like to share you can post them on either the mykidstime FB page or on the Wholesome Ireland FB page & we’ll share them so that everybody can see how well it turned out for you. Way to go!