Ingredients

For the cake: 600g local unsalted butter, softened 600g caster sugar 9 large free range eggs, lightly beaten 600g self raising flour, sifted, plus extra for dusting ¾ tsp salt 90ml local milk, semi skimmed/reduced fat 2½ tsp vanilla extract Food colouring (purple, blue, green, yellow, orange and red) For the cream cheese icing: 600g local unsalted butter, softened 750g icing sugar 600g full fat cream cheese 1 tsp vanilla extract For the drizzle icing: 200g icing sugar, sifted 1 large egg white, lightly beaten ½ tsp lemon juice Food colouring (purple, blue, green, yellow, orange and red) 1 pack Hundreds and Thousands/sprinkles You will need: 6 clean piping bags 3x 20cm cake tins 3 x 15cm cake tins 1 pallet knife or icing scraper;

Method

Preheat the oven to 180°C/fan 160°C/Gas 4 Grease and line all 6 cake tins For the 20cm base tier, whisk 400g of the butter and 400g of the sugar together using an electric whisk until light and fluffy. Add 6 eggs, one at a time, whisking well after each addition, then sift in 400g of the flour and 1/2 tsp of the salt Fold with a large spoon until just combined Stir in 60ml of the milk and 1½ tsp of the vanilla extract, then weigh the whole mixture Divide the weight by 3 and spoon each third into a separate bowl Add one each of the purple, blue or green food colourings to each bowl, until you reach your required intensity of colour Transfer to the 3 x 20cm tins and bake in the oven for 25-30 mins, or until a skewer inserted into the centre comes out clean Leave the cakes to cool in their tins for 5 mins before turning out to cool completely Meanwhile follow the steps again to make the sponge for the 15cm top tier – using 200g butter, 200g sugar, 3 eggs, 200g flour, ¼ tsp salt, 30ml milk and 1 tsp vanilla extract This time, use the yellow, orange and red food colourings Once all the cakes are cool, use a serrated knife to trim the tops to make the cakes level Lightly trim or scrape away any discoloured edges too Next, make the cream cheese icing Whisk the butter and icing sugar together until light and fluffy Gradually add the cream cheese a spoonful at a time, whisking until combined Add 1 tsp of vanilla extract and whisk for 1 more minute Sandwich the 3 x 20cm sponges together using a few tablespoons of the icing between each layer Start with the purple sponge, then the blue, then the green Separately sandwich the yellow, orange and red sponges together so the red is at the top Cover both cakes completely with the remaining icing, using a pallet knife or icing scraper to create a smooth surface Leave to set in the fridge for 1 hour before decorating For the drizzle icing, put the icing sugar in a bowl and add the beaten egg white and lemon juice Whisk on a low speed for 2-3 mins until you have a smooth, stiff-peak consistency Stir in 1 tbsp cold water until you have a thick but just runny icing that will dribble slowly down the cake Test on a plate to see how quickly it dribbles, and add 1-2 tsp more water if needed Divide between 6 bowls and add a little food colouring to each, then spoon into piping bags Take the cakes out of the fridge and put the small one on the top of the larger one Use the hundreds and thousands to create a band around the bottom tier Then, using a skewer or knife, lightly indent the top tier to make marks where the colour wheel will go – you'll need 12 wedge shapes Use the piping bags to pipe the wedges (in the order purple, blue, green, yellow, orange and red) round the cake twice Finally, gently encourage dribbles to come down the sides of the top tier and begin dribbling down the second tier Leave to set, then enjoy!