Preheat the oven to moderate 180c.brush a baking tin with oil or butter,dust lightly with flour, shake off excess.
Using electric beaters, beat butter and sugar until light and creamy.
Add eggs, gradually beating thoroughly after each addition.
Fold in the flour plus the baking powder until you have the right mixture.separete the batter into two,mix one with vanilla essence, the other cocoa.pour the one with vanilla first on the prepared tin, followed by cocoa mixture, making a nice partern.bake for 45 min or till the skwer cmes out clean when inserted,remove from the oven,let it cool for ten minutes before putting it on rack.
