- Preheat oven to 150'C fan-forced.
- Place the water, butter and cocoa in a saucepan over medium heat and stir until the butter has melted. Place the flour, bicarbonate of soda and sugar in a bowl, add the cocoa mixture and whisk to combine. Add the eggs, buttermilk and vanilla and whisk to combine. Divide mixture between 2 lightly greased 12cm round cake tins lined with non-stick baking paper. Bake for 40-45 minutes or until cooked when tested with a skewer. Allow to cool in the tins for 5 minutes. Turn out onto wire racks to cool completely.
- While the cake is baking, make the cream cheese frosting. Place the butter and cheese in the bowl of an electric mixer and beat for 6–8 minutes or until pale and creamy. Add the icing sugar and cocoa and beat for a further 6–8 minutes or until light and fluffy.
- To assemble, slice the cakes in half horizontally. Place one cake layer on a plate and spread with one quarter of the frosting. Repeat with remaining layers and frosting. Decorate as desired.