slightly adapted from Lorraine Pascale's Fast, Fresh and Easy Food
250ml Sunflower oil
250g caster sugar
100ml low fat milk
4 eggs, at room temperature
1 teaspoon vanilla extract
300g self-raising flour
1 teaspoon baking powder
2 pinches of salt
25g cocoa powder
Preheat the oven to 180 degrees C and spray a 23cm round springform cake pan with cooking oil spray. Line the base of the pan with baking paper.
In a large mixing bowl, use a hand-held whisk to combine the oil, sugar, milk, eggs and vanilla extract.
Pour 400g of this mixture into a separate bowl.
Sift 175g of the self-raising flour into one of the bowls with a pinch of salt and 1/2 teaspoon of the baking power. Mix well and set aside. This the vanilla batter.
Sift the remaining 125g self-raising flour, a pinch of salt and the other 1/2 teaspoon of baking powder into the other bowl along with the cocoa powder and mix it all together and set aside. This is the chocolate batter.
Pour the vanilla batter into a disposable piping bag and the chocolate batter into a separate disposable piping bag. Cut a small opening at the end of each piping bag.
Pipe a tablespoon of the vanilla batter into the middle of the prepared cake pan, then pipe a tablespoon of the chocolate batter into the middle of the vanilla batter. Keep alternating between vanilla batter and chocolate batter until all the batter is used. As you pipe each portion, the batter will slowly spread out to the sides of the pan.
Bake for 35 minutes, or until a toothpick inserted into the centre of the cake comes out clean.
Leave the cake to cool in the pan for about 5 minutes, then remove from the pan and leave to cool completely on a wire rack.