This is my mum's chocolate cake recipe which she used to make for all the birthdays in our house. Now I make it for my family! The secret is to add whisked egg whites so the chocolate sponge cake is light.
Sponge Cake: Preheat the oven to 180 degrees C. Lightly grease 2 (20cm) sandwich cake tins.
Use an electric mixer or beaters to cream the butter and sugar together until the mixture is smooth. Add the egg yolks and continue to beat until light and fluffy, about 5 minutes.
Stir the melted and cooled chocolate into the milk then mix well. Add to egg mixture, then gradually mix in flour and baking powder; beat for another minute until mixture is an even colour.
In a separate bowl, whisk egg whites until stiff. Gently fold the egg whites into the chocolate cake mixture until evenly mixed. Divide the mixture between the 2 cake tins.
Bake for 30 minutes or until a skewer inserted into the centre comes out clean. Cool on a wire rack.
Chocolate Buttercream: Blend the softened butter and icing sugar in a food processor or beat together with an electric beater. Add the melted chocolate and vanilla then stir together until evenly mixed.
When the cake has cooled, use a long serrated knife to slice throught the middle of each cake, creating 4 layers.
Spread the chocolate buttercream over each layer and then over the top. Decorate with whatever cake decorations you like.