Step 1

Grease and line two 8-inch round cake pans with baking or parchment paper. Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced.

Step 2

In a large mixing bowl, add butter and sugars and beat with an electric mixer until pale and creamy.

Step 3

Add vanilla and eggs, one at a time, and continue to beat until mixture is combined and creamy. Boil the kettle and pour out 1/2 cup water and set aside.

Step 4

In a separate bowl, sift plain flour, cocoa powder, baking powder, baking soda and salt and lightly whisk.

Step 5

Add dry ingredients to the wet, along with the hot water and gently fold with a spatula. Finally, add the sour cream and fold until the mixture is completely combined and smooth. It will be quite thick – this is fine.

Step 6

Divide chocolate batter into prepared cake pans and bake for approximately 35-40 minutes or until a skewer inserted into the middle of the cake comes out clean. Leave the cakes to cool for about 10 minutes before carefully transferring to a wire rack to cool completely.

Step 7

Make a batch of real chocolate buttercream and cover the middle, top and sides of the chocolate cakes.