Preheat the oven at 180 °c. Cream butter and sugar together, add oil, eggs and vanilla and beat till smooth. Sift in flour and baking powder, make a well in the center and add the milk. Mix to form a smooth batter and take out 1 cup of batter and place in a separate bowl.Mix the cocoa and water together to form a paste. Add the chocolate paste to the 1 cup of batter and mix through.Grease or line 2 round pans and add bout 4 big spoons of vanilla batter in each pan and smooth it evenly out.

Place the chocolate batter in a piping bag and from the center of the pan make a circular motion till the edge of the pans. Cover the pans with the rest of the vanilla batter and even it out. Take the chocolate batter and pipe a circle again same as before.Run a knife from the center of the cake to the edge of the pan as if you cutting the cake, don't go deep just on the top. Do this right around till a web is formed. Bake for 25 mins. Leave to cool.

Prepare the ganache by melting 1 Tbs butter with a 1/3 cup of milk, add 150g choc pieces and stir. Leave to thicken slightly and spread evenly on 1 layer, finally add the other layer of cake on top.