Instructions

1. Grease and line three 6-inch round baking pans (or two 8-inch round baking pans). Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced.
2. In a large mixing bowl, add the butter, sugar and vanilla and beat with an electric mixer until smooth and creamy.
3. Add eggs, one at a time, beating after each addition. Sift in flour and baking powder. Add milk and sour cream and beat on a low speed until combined. Finally, chocolate chips and stir.
4. Divide batter evenly between cake tins and bake in the oven for approximately 30 minutes or until a skewer inserted in the middle comes out clean. Carefully remove the cakes and set on a wire rack to cool completely.
5. To make frosting, beat butter with an electric mixer until smooth and creamy, then add the vanilla. Add icing sugar, one cup at a time. Add a tablespoon of milk as needed. Continue until you have used all the icing sugar and milk and the frosting is smooth and creamy.
6. Use a serrated knife or a cake trimmer to even the top of both cakes. Place one cake on a small cake board, then cover the top with buttercream. Place the second cake on top. Cover top with buttercream.
7.  Add third cake on top. Cover the entire cake, top and sides, with remaining buttercream. Use a cake scraper to remove excess buttercream on the sides. Sprinkles chocolate chips on top.