How to make the Best Ever Rainbow Cake | Cupcake Jemma

There isn’t a person on earth who isn’t a fan of rainbows, right? Right?? Well, if there is then they must be very sad and lonely. But you and I know that rainbows are magical and brilliant and what better way to give the rainbow the respect it deserves than to embody it in cake form.

This one’s quite a lengthy watch, so put the kettle on, put your feet up and prepare for some top tips for baking and decorating the perfect Rainbow Cake. This video is going to knock your socks off!


For the cake –
9 tbsp whole milk
1 ½ tsp vanilla extract
Various colour pastes (red, orange, yellow, green, blue & purple)
750g soft unsalted butter
750g caster sugar
9 large free-range eggs
750g sifted self-raising flour
Butter & flour for preparing the cake tins

For the buttercream –
400g soft unsalted butter
900g sifted icing sugar
5-6 tbs whole milk
½ tsp vanilla extract



21 thoughts on “How to make the Best Ever Rainbow Cake | Cupcake Jemma”

  1. Hi Ms Gemma.
    You can forego the white bowl in 5:20 when you measure the weight.
    You weigh the metallic mixing bowl prior to putting in the ingredients; then weigh it again after the mixing.
    That would be ONE LESS BOWL TO CLEAN.
    Just a question:
    If white light goes through a prism and produces ROYGBIV colors…. would mixing these six food colors that you have produce white color?

  2. You're super cute and super talented Jemma! Always an inspiration for an amateur baker like me!! Love you and your videos ❤❤

  3. I made this cake yesterday for my daughter's 1st birthday. It went down so well! Thanks so much for the great tutorial – the step by step instructions were really helpful 😀

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