Rainbow Kids' Birthday Cake
·Egg yolk mixture and whisked whites
Separate the eggs into yolks and whites. Beat the yolks with the sugar, and whisk the whites into stiff peaks (adding a pinch of salt).
Fold the yolks and whisked whites into the flour
Mix the flour with the baking powder and sift it through a fine sieve into a bowl. Add the sweetened yolks, then gently fold in the whisked egg whites.
Six colourful bowls
Divide the batter between six smaller bowls and tint each one with the colour you want. A little food colouring really goes a long way — I actually overdid a few of the layers, which could have turned out much lighter.
Pouring into the tin
Pour the colours one by one into a cake tin greased with fat and dusted with flour. I use spray oil for greasing, which means there's no need to dust the tin with flour afterwards.
Bake
Bake in an oven preheated to 180 °C for about 7 minutes.
Filling cream
What you use to fill and cover the cake comes down to personal taste. I used whipped mascarpone with sour cream and a bit of sugar.
Decorate and let it rest
I kept the cream plain white, which makes a lovely contrast against the colourful sponge layers. Fill the cake with the cream, cover it all over, and leave it to chill, ideally overnight.