Preheat oven to 180°C. Line 4 20cm round cake tins with baking paper and grease the sides.
Cream the butter with an electric mixer until smooth in a large bowl.
Gradually add the sugar and beat for 3 minutes until fluffy.
Add the eggs one at a time, beating well after each addition.
Sift the 2 flours and salt into a separate bowl.
Add the dry ingredients in 3 parts, alternating with the milk and vanilla. Do not overmix!
Divide the mixture into 4 separate bowls (I used digital scales for accuracy).
For the top layer, add no colouring and 1-2 tablespoons of coconut essence.
For the second layer, add a tiny drop of pink food dye and 1 teaspoon of coconut essence.
For the third layer, add more pink food dye and 1 teaspoon of strawberry essence.
For the bottom layer, add a generous amount of pink food dye and 1-2 tablespoons of strawberry essence. Try and stir each bowl as gently as possible.
Pour each batter into their lined cake tins and bake for 20-25 minutes until lightly golden brown.
Allow to cool in the tin for 15 minutes, then turn out onto a wire rack.