Tuesday Tutorial – How to make a Rainbow Cake!

This week we’re showing you how to make a rainbow cake – a surprisingly simple cake that ensures plenty of jaw-dropping when cut!

Equipment you’ll need…

Mixer (Standing or hand)
Mixing bowl (plus 5 little ones)
Sandwich tins (this recipe is for a 6″ cake – not trimmed)
Cake splitter
Cake scraper (for smooth buttercream)
Chosen decoration (I used millions of sprinkles)


285g Unsalted butter
285g Caster Sugar
255g Self raising flour
100g Plain flour
4 Eggs
2 tsp Vanilla extract
Sugarflair gel colours – I used Grape Violet, Navy, Egg Yellow, Pink and Party Green

1. Turn your oven to 160C and grease all of your sandwich tins. Mix all of your ingredients together (apart from the gel colours) until the mixture is free of lumps, lovely and smooth. Be careful not to overmix as this will affect how much your cakes rise.

2. Split your mixture between 5 small bowls (roughly 225g per bowl) and colour each a different one of your colours. Spoon into your cake tins and bake each one for roughly 20 minutes. Times and temperatures may vary so cook cakes accordingly and check they’re baked by inserting a skewer into the centre – if it comes out clean your cake is done!

TIP! You don’t need 5 sandwich tins to make a fab rainbow cake, just cool, clean and regrease each tin after use and reuse, remembering not to open the oven door while you have cakes halfway cooked in the oven.

3. Cool each cake. Use the splitter to make your cakes level and all roughly the same height. You can use a bread knife for this bit but it may make your cake a bit on the wonky side! Choose your colour pattern and stack your cakes, adding a generous layer of buttercream between each one.

TIP! Don’t worry if your cakes don’t look super bright at this stage – as we didn’t trim them we can only see the outside of them, which will have baked a little more and look darker in colour.

4. Now apply buttercream all over your cake, making it perfectly smooth with your scraper.

5. Now apply decoration – we’ve always got lots of sprinkles lying around at BDB HQ so we treated ours to a complete coating!

6. Now all that’s left to do is find an audience and dramatically cut your cake, then wait for the ooohs and aaaahs…

If you’d like to learn how to cut, split, smooth and cover a cake hands on, we show you how it all works in any of our larger cake classes, HERE

Enjoy and please don’t forget to send us some photos of your creations on our Facebook Page!

Jenny x



12 Responses to Tuesday Tutorial – How to make a Rainbow Cake!

    • Hi Sophie, as with all sponges, they’re best eaten fresh, especially with the buttercream. So we wouldn’t recommend keeping it longer than a few days! And how long it takes depends on the amount of tins you have! But we made this one with just two tins and it took us a short afternoon 🙂 Jenny x

  1. Hi What sort of food colouring do you use to make such bright colours? Im struggling at the moment as i use liquid ones from supermarkets and find they either dont colour well or leave a horrible taste. I usually have to use 1/4-1/2 of the bottle just to get a meduim shade 🙁 thanks. x
    P.s Great looking cake!! I always look forward to a tuesday 🙂

  2. I love this recipe because its in the uk and all the others are in diffrent countries and my 7 year old sister loves it so much.
    So thankyou!!!

    • Hi Louise, it’s a classic Madeira sponge, so it’s a little bit more sturdy than a Victoria sponge as it has lots of layers.

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