Preheat oven to 180°C.

Mix bake mix, melted butter, milk, water and sugar until batter is smooth.

Grease and flour a 7inch dia. baking pan.

To make a ring cake grease and flour the outside of a 2inch metal bowl and place it inside the baking pan.

Pour 2/3 of the batter in the outer pan. Add cocoa powder to the remaining batter, mix and put on top of the other batter.

Swirl a fork through the batter for a marble effect and bake for 15 minutes and make a cut around the cake to ensure a crack in the center.

Continue baking for another 15 minutes or until a toothpick inserted in the center comes out clean.