Watermelon Cake

SPONGE CAKE INGREDIENTS:
160g salted butter, softened 1/2 tsp fine salt
560g caster sugar 1 tsp vanilla extract
480g cake flour 4 large eggs, at room temperature
30ml (2 tbsp) baking powder 480ml full cream milk, at room temperature
Food colouring of choice

DIRECTIONS:
To make the sponge, preheat the oven to 190 degrees celsius.
Grease and line 6 x 20/15cm cake tins with baking paper.
Using an electric handheld or stand mixer (with the paddle attachment), place the butter, sugar, flour and baking powder in the bowl and mix on low speed until it resembles a sandy breadcrumb texture.
Whisk together the milk, vanilla and eggs then, with the speed still on low, gradually pour the liquid into the dry ingredients.
Beat the batter until smooth and light – about 2 minutes.
Divide the cake batter into 6 bowls to add food colouring of choice.
Divide the cake batter in between your lined tins.
Bake in the preheated oven for 20-25 minutes or until golden, springy to the touch and a skewer comes out clean.
Allow the layers to cool completely before levelling them off by cutting off the tops with a bread knife.

SWISS MERINGUE BUTTERCREAM INGREDIENTS:
7 egg whites
450g unsalted butter
400g gradulated sugar
2.25ml vanilla essence
2ml lemon juice
Watermelon flavouring
Red, Green, Black food colouring

DIRECTIONS:
Fill a pot with water and place on stove to bring to boil (double boiler). Crack eggs and add sugar to mixing bowl. Place bowl with egg whites and sugar mixture over simmering water. Immediately start whisking until mixture is smooth to touch (no sugar granules). Transfer bowl to stand mixer and whisk for 10 minutes until the bowl is cool to touch (stiff peak). Switch to a paddle attachment and mix on low speed and add the cubes of butter (one at a time) until incorporated. Turn mixer to max speed and beat for 10 minutes (after 3 minutes it will look curdled but keep mixing). Add lemon juice and vamilla essence and keep mixing.
Divide the swiss meringue buttercream into 5 bowls.
In one bowl add watermelon flavouring to your taste.
In the other 3 bowls add green, red and black leaving one bowl plain white.