METHOD

1. Preheat oven to 160°C (325°F). Lightly grease 12cm, 18cm and 22cm round cake tins and line with non-stick baking paper. Place the flour, sugar, cocoa, eggs, milk, butter and vanilla in a large bowl and whisk until smooth. Pour the mixture into each tin until each is three-quarters full. 
   
2. Cook the 12cm cake for 1 hour, the 18cm cake for 1 hour 10 minutes and the 22cm cake for 1 hour 20 minutes, or until cooked when tested with a skewer. Allow to cool in the tins for 10 minutes before turning out onto a wire rack to cool completely. 
   
3. To make the icing, place the butter, cream cheese and icing sugar in the bowl of an electric mixer and beat for 10 minutes, scraping down the sides of the bowl, or until light and fluffy. 
   
4. Place 3½ cups of the icing in one bowl, add 2–3 drops of blue food colouring and mix to combine. Place 2 cups of the icing in a second bowl, add 2–3 drops of pink food colouring and mix to combine. Place the remaining icing in a third bowl. 
   
5. To assemble the cake, trim the top of the cakes and discard. Halve each cake horizontally to make 6 even layers. Place the bottom layer of the largest cake on a cake stand or serving plate and, using a palette knife, spread with 1 cup of the blue icing. 
   
6. Place the top layer of the largest cake on top and spread ¾ cup of the blue icing over the top and sides of the cake. Refrigerate for 10 minutes to firm slightly. 
   
7. Place the remaining blue icing in a piping bag fitted with a 2cm round nozzle. Starting at the base of the cake, pipe a small round of icing and, using a palette knife, use a flat sideways stroke to create a wave. Repeat piping and stroking the icing around the circumference of the cake+. 
   
8. Place the bottom layer of the medium cake on top and spread with ⅔ cup of the pink icing. Place the top layer of the medium cake on top and spread the remaining pink icing over the top and sides of the cake. Refrigerate for 10 minutes to firm slightly. 
   
9. Place the bottom layer of the small cake on top and spread with ⅓ cup of the white icing. Place the top layer of the small cake on top and spread ¼ cup of the white icing over the top and sides of the cake. Refrigerate for 10 minutes to firm slightly. 
   
10. Place the remaining white icing in a clean piping bag fitted with a 1cm round nozzle. Starting at the base of the cake, pipe a small round of icing and, using a palette knife, use a flat upward stroke to create a wave. 
    
11. Repeat piping and stroking the icing around the circumference of the cake+. Sprinkle the top of the cake with hundreds and thousands to serve. Serves 12–16. 
    

+ If the icing is a little soft, place the cake in the refrigerator for 10 minutes to firm slightly.