- Melted butter, to grease
- 200g butter, softened
- 215g (1 cup) caster sugar
- 1 teaspoon vanilla essence
- 3 eggs
- 150g (1 cup) self-raising flour
- 150g (1 cup) plain flour
- 125ml (1/2 cup) milk
- 2-3 drops red liquid food colouring
- 1 tablespoon cocoa powder, sifted
- 100g soft butter
- 300g (2 cups) icing sugar mixture
- 1 tablespoon cocoa powder
- 2 tablespoons milk
Preheat oven to 180°C. Brush a square 20cm (base measurement) cake pan with melted butter to lightly grease. Line with non-stick baking paper.
Use an electric beater to beat the butter, sugar and vanilla essence in a medium bowl until pale and creamy. Add the eggs, one at a time, beating well after each addition until well combined. Sift together the flours. Reserve 2 tablespoons of the milk. Fold half the flour mixture into the butter mixture and stir in half the milk. Repeat with remaining flour mixture and milk until well combined.
Divide the cake batter among 3 bowls. Add a few of drops of red liquid food colouring to 1 portion and stir until well combined. Combine the cocoa powder with the reserved milk and add to another portion. Stir until well combined.
Place alternate spoonfuls of the 3 mixtures into the prepared pan, tapping the base of the pan on a flat surface to settle the mixture. Use a spoon to gently swirl the batters together to create a marble effect. Tap the base of the pan on a flat surface to smooth the surface. Bake in preheated oven for 45-50 minutes or until a skewer inserted into the centre comes out clean. Remove from oven and set aside in pan for 5 minutes. Turn onto a cake rack to cool completely.
To make the chocolate frosting, place butter in a large bowl and use an electric beater to briefly beat until creamy. Sift over the combined icing sugar and cocoa powder, and beat until combined. Add the milk and beat until fluffy.
Spread frosting over the cake using a round-bladed knife to create swirls. Cut into slices and serve immediately.