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This recipe is classed as advanced

Rating 3.32 / 5 (449 votes)

Prep time:
1 hr
Cook time:
45 min
Serves:
Serves 18

Edd Kimber’s rainbow cake recipe makes a spectacular cake, with white frosting hiding the multicoloured rainbow inside

Method

1. Preheat the oven to 180C/160C fan/gas 4. Grease and line 3 x 20cm round cake tins with baking parchment, greasing the parchment too.

2. In a medium bowl, whisk the flour, cornflour, baking powder and ½ teaspoon of salt together to combine, then set aside.

3. Put the butter into a large bowl and using an electric mixer, beat on medium-high speed until smooth and light. Add the sugar and beat until light and fluffy, about 5 minutes, then add the vanilla extract and mix to combine. With the mixer on medium speed, add the egg yolks, one at a time, beating each until fully combined before adding the next. With the mixer on low, sift in the flour mixture in three additions, alternating with the milk, starting and finishing with the flour.

4. Put the egg whites into a clean bowl and whisk until they hold soft peaks. Add the egg whites to the cake batter and gently fold together until just combined and there are no streaks of white. Divide the batter equally between 6 small bowls. Add a small amount of each food colouring to each bowl, enough to make it a vibrant colour.

5. Add the first 3 bowls to the prepared tins, one colour per tin, and bake for 15 minutes, or until they spring back when touched lightly. Allow to cool in the tins for 10 minutes before turning out onto a wire rack to cool completely. Repeat with the remaining 3 portions of batter.

6. For the frosting: melt the chocolate in a heatproof bowl set over a pan of gently simmering water, making sure the base of the bowl doesn’t touch the water. Remove from the heat and allow to cool.

7. Put 190ml water and the sugar into a pan over medium heat. Bring to the boil and have a sugar thermometer ready. Meanwhile, put the egg whites into a clean bowl, ideally of a freestanding electric mixer. Start whisking the egg whites on high speed when the syrup in the pan reaches about 115C on the sugar thermometer. Cook until the syrup registers 121C. With the mixer still running, pour the syrup in a slow stream down the side of the bowl containing the egg whites, avoiding the beaters. Continue whisking on high speed until the meringue is at room temperature.

8. With the mixer on medium-high speed, add the butter a few pieces at a time, beating until fully combined. When adding the butter, it can sometimes look curdled so if this happens don’t worry, just keep mixing and eventually it will smooth out to form a light buttercream frosting. With the mixer on medium speed, pour in the melted chocolate and mix until fully combined.

9. To assemble the cake, put the purple cake layer on a cardboard cake board or serving plate and top with a thin layer of frosting. Repeat the process with the other cake layers in the order of a rainbow - purple, blue, green yellow, orange, red. Spread the remaining frosting across the top and sides of the cake.


Want to try making a rainbow cake as a cute gift? Take a look at our rainbow cake in a jar recipe

Looking for a cake with wow factor? Try our celebration cake recipes



Ingredients

  • 225 g unsalted butter, at room temperature, plus extra for greasing
  • 325 g plain flour
  • 50 g cornflour
  • 4½ tsp baking powder
  • 400 g caster sugar
  • 2 tsp vanilla extract
  • 4 medium eggs, separated and lightly beaten
  • 300 ml whole milk
  • gel food colouring, in red, yellow, orange, purple, blue and green

For the white chocolate Italian meringue frosting

  • 150 g white chocolate
  • 300 g caster sugar
  • 6 medium egg whites
  • 540 g unsalted butter, at room temperature

Tips and suggestions

Want to try making a rainbow cake as an individual gift? Take a look at our rainbow cake in a jar recipe

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Latest Comment

 

I weighed the cake mixture, so I could divide it evenly into 7, then could weigh, colour and bake them one by one. By the time I had done the 3rd, the first was baked, so it was quite fast. I covered it in white chocolate frosting, and it looked impressively large. But when it was cut, it looked amazing. The cake probably had more photos taken than the birthday boy! Lots of complements!

FionaR16407 FionaR16407  Posted 11 Aug 2013 10:49 AM
 

I made this rainbow sponge and covered it with marble effect fondant, made a unicorn out of fondant and placed it on top for my granduaghters 6th birthday..it took a lot of patience but her huge smile when she saw it made it all worthwhile!! Everyone was well impressed, tried to upload a pic but nothing doing.

CarolB5339 CarolB5339  Posted 23 Feb 2013 8:47 PM
 


EimearH88347 EimearH88347  Posted 31 Jan 2013 3:14 PM
 

EimearH88347 EimearH88347 Posted 31 Jan 2013 3:14 PM