• Delicious and bright rainbow cake with vanilla buttercream, pink drip and sprinkles!
  • Welcome to the most requested recipe of all time. I'm not kidding, I've been asked for this recipe over and over again, and I'm finally posting it on my blog! It took way too long because I wanted to get it right!
  • I love everything about cake, we all know this, but rainbow cake is something else. The super bright colours, the sweet taste, and all the cute things take it to a whole different level! It's just glorious.

  • So... I'll say from the start that this recipe uses lots and lots of ingredients, and it's a huge cake! Like, the six cake layers, all the buttercream in between the layers, and all the decoration on top!
  • And I will also say from the beginning ... Yes, I know that the rainbow has seven colors. This cake, only six. When baking this cake, I just find making 6 colors is much easier, and you can see the obvious differences. I'm not bothered by the seventh!
  • Red, orange, yellow, green, blue, purple... the primary colors you need in your life. I made up a bit for the lack of seven by adding a pink drip on the outside but we'll get to that later.

  • For this cake, I made probably the biggest cake ever. It measures about 8-9 inches in height, and uses several components. Because it is a six layer cake I decided to make it in two batches. So three layers at a time, so you still only need three cans!
  • I made a cake mix of 600g, so it is very easy to divide it into two batches. The best way is to weigh 5-6 medium eggs, as close to 300 grams as possible, for example 312 grams, and then match the butter, sugar and flour to this weight.

  • Next, you mix them together as usual, then divide them into three bowls. It doesn't matter what colors you paint first, but I did red, orange, and yellow together, then green, blue, and purple.
  • The oven temperature is a little lower than usual, I don't want the sponge to brown too much. This also somewhat comes from the color brands you use! Red food coloring, orange food coloring, yellow food coloring, green food coloring, blue food coloring, purple food coloring. For sponge mixtures!
  • Once my sponge is baked, I let it cool completely and freeze it wrapped in cling film overnight so it's easy to decorate the next day - but this part is completely optional of course!!
  • For the buttercream you are using 750g of unsalted butter and 1,500g of icing sugar which is technically a bit outrageous but the serving amount of this cake is huge so please don't be negative about the sugar content!

  • I make my buttercream as usual by beating unsalted butter at room temperature alone for several minutes to make it really loose and fluffy, then gradually adding the powdered sugar! I make sure to beat this for a long time.
  • You can do several ways to get the whiter buttercream, by whisking the buttercream on its own for longer, or using a smidge of purple buttercream to counteract the yellow, but I love using this white food coloring!

  • I add a little at a time and keep beating it well to make sure it's really white and bright to contrast with the colors of the sponge! However, making the buttercream whiter is completely optional.
  • When I start decorating the cake I put a few tablespoons of butter on each sponge and smooth it out, making sure the colors in the sponge are arranged correctly of course...!
  • Once each sponge is layered, you need to make a layer of crumbs using as little buttercream as possible around the edges to seal the spare crumbs out of the sponge! Then I refrigerate the cake for some time to set before adding another layer of buttercream on top.
  • I use a large metal detector to decorate the sides of the cake, and a small angled spatula to also help coat the sponge - which is much easier and you'll get a smoother finish using these too!

  • Just like I'm done with the buttercream, I carefully press in some rainbow sprinkles into the bottom of the cake to get a bit of color and I just love the design - be warned that the sprinkles will fall off at this point, so beware! After that, cool the cake again!
  • For the pink dab I use white chocolate ganache with the addition of this pink food coloring. It's a super bright color so you don't need to add much and that means you're getting the best color drip ever!

  • Then I top up the remaining buttercream and add more rainbow sprinkles and you're done with the best cake ever! I love the sponge and how shiny and beautiful it is - but the main point to make it clear, you need to use high quality colours.
  • Using supermarket colours, it won't work well, or maybe at all...so please don't waste ingredients by doing this! The colors are 100% worth the investment because they last so long! Any questions, leave them below in the comments and happy baking! x



  • 600 g Eggs (weigh eggs in shell) (about 10-12 medium eggs)
  • 600* g Unsalted butter/stork
  • 600* g Caster sugar
  • 600* g Self raising flour
  • 1/2 tsp Red, Orange, Yellow, Green, Blue, Purple food cololuring


  • 750 g Unsalted butter (room temp, not stork)
  • 1500 g Icing sugar
  • 1 tsp Vanilla extract
  • 1-2 tsp White food colouring


  • 180 g White chocolate
  • 75 ml Double Cream
  • 1/2 tsp Pink food colouring
  • Rainbow Sprinkles


For the Cake

  • Preheat your oven to 160ºc/140º fan and line three 8"/20cm springform tins with parchment paper and leave to the side for now.
  • Weigh 5-6 medium eggs in their shells and get as close to 300g as possible (e.g. 312g)
  • Then add 312g of butter and caster sugar to a bowl and beat until light and fluffy.
  • Add in the eggs, and 312g of self raising flour and beat again until smooth.
  • Split the mixture evenly into three bowls, and add three of the colours each (for example, red, yellow and orange.)
  • Bake the cakes in the oven for 30 minutes (or until baked - test with a skewer).
  • Once baked, leave the cakes to cool in the tin for 10 minutes before removing to a wire rack to cool fully.
  • Repeat this process again and use the other three colours (for example, green, blue and purple!). Once all the cakes are baked, leave them all to cool fully.
  • (You can wrap the sponges in clingfilm once they have cooled and freeze over night to make decoratin easier but this is optional!)


  • Once all of your cakes are cooled, you can make the buttercream.
  • Beat the room temperature unsalted butter on its own for a few minutes to soften it and make it supple.
  • Gradually add the icing sugar beating very well each time until its all mixed in.
  • Keep beating and add the white food colouring and vanilla extract and beat for a few minutes.
  • Buttercream Decoration
  • Using a 10" cake board, add your first sponge. I start with purple as its the bottom colour.
  • Add a couple tablespoons of the buttercream on to the sponge and smooth over. Repeat this with blue sponge, then green, yellow, orange and finally red at the top.
  • Using a small amount of buttercream, smooth over the sides of the cakes and fill in any gaps and create a crumb coat.
  • Refrigerate or freeze the cake on the board for an hour or so to chill and firm to make the next stage of decorating easier.
  • Once chilled, add on lots more buttercream around the sides of the cake with a small angled spatula, and smooth over using a large metal scraper until the sides of the cake are smooth like in the photos!
  • Carefully press some of the sprinkles into the bottom of the cake using the palm of your hand to create the sprinkle effect!
  • Once this has been done, refrigerate again whilst you make the drip!


  • Add the white chocolate and double cream to a bowl and heat in a microwave in short 10 second bursts stiring well each time.
  • Once melted and combined, add the pink food colouring and mix until smooth!
  • Add the pink ganache to a piping bag and carefully cut off the end and drip down the sides of the cake. The more you push over the side of the cake with the piping bag, the further it will drip!
  • Add the leftover buttercream to a piping bag with your favourite piping tip and pipe swirls of buttercream onto the top of the cake (like I have done in the photos)
  • Finally sprinkle on some etra sprinkles and leave the cake to set in the fridge fully.
  • In the hot weather I store the cake in the fridge until it has been portioned.


  • This cake lasts 4-5+ days once made!
  • The colours that you use and what order are up to you, this recipe is just how I did it! You can swap up the order or whatever you prefer!
  • You should avoid supermarket colours as they are not strong enough. 
  • In this recipe use:
  1. This red food colouring
  2. This orange food colouring
  3. This yellow food colouring
  4. This green food colouring 
  5. This blue food colouring
  6. This purple food colouring
  7. This white food colouring
  8. This pink food colouring 
  9. This piping bag 
  10. This piping tip 
  11. This metal scraper 
  12. This white chocolate 

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