For the cake
- 288g plain flour
- 2 tsp baking powder
- ½ tsp salt
- 113g butter
- 268g granulated sugar
- 1 tsp vanilla extract
- 4 egg whites
- 180ml milk
- Food colourings ─ we used Wilton® Colour Right System Food Colourings
- Preheat the oven to 160°C/Gas 3 and lightly grease the 5 cake pans with Wilton Cake Release.
- Sift the flour, baking powder and salt into a bowl and set aside. Place the butter and sugar into the stand mixer bowl and beat until light and fluffy. Add the egg whites one at a time, beating well after each addition. Add the vanilla extract and beat well. Add the flour mixture a little at a time, alternating with the milk beat until just combined.
- Divide the mixture evenly into 5 bowls then add your chosen colours using a cocktail stick ─ take care to add just a little at a time, then keep adding a little more until you reach your desired shades.
- Transfer the mixtures into the pans, spreading them evenly, then make a slight dip in the centre of each to help to achieve an even rise.
- Place all the pans in the oven, evenly spaced, and bake for 17-20 minutes or until a skewer inserted into the middle of each cake comes out clean. Set aside and cool for 5 minutes then remove from the pans and transfer to a wire rack to cool completely.
- To assemble the cake, smear a small amount of frosting on a cake stand or plate and secure the first sponge on this, then spread a layer of frosting on top and place the next sponge on top of that. Repeat with the remaining sponges, until all 5 layers are stacked. Use a palette knife to spread the remaining frosting evenly around the sides and on top of the cake.
- With your hand or a small palette knife, gently press the sprinkles into the icing, starting at the bottom and working your way to the top of the cake, checking there are no gaps where you can see the frosting.