Beat the margarine and the sugar until pale and fluffy

Add in one egg at a time beating to incorporate it before adding another one

Sift your flour and baking powder in a separate bowl. Add the sifted flour into the mixture bit by bit while folding it in.

Divide the batter into two bowls. In one bowl, add the cocoa powder and mix in well.

Prepare your baking tin. Add the mixture in layers of the portion with cocoa and without.

Bake at 165 degrees for 1 hour