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!