Heat oven to 180C
Cream butter and sugar, add eggs one at a time and beat well.
Fold through the flour, milk and vanilla extract until the mixture is smooth.
Divide the mixture between 2 bowls.
Stir the cocoa powder into the mixture in one of the bowls.
Take 2 spoons and use them to dollop the chocolate and vanilla cake mixes into the tin alternately.
Take a skewer and swirl it around the mixture in the tin a few times to create a marbled effect.
Bake the cake for 45-55 mins until a skewer inserted into the centre comes out clean. Turn out onto a cooling rack and leave to cool.
Recipe Credit: BBC GoodFood Magazine
Prepared, tried and tested by: Preshana Singh