3 simple steps
Preheat: oven to 180deg c. Grease the pan with butter and lightly flour
Beat cake mix,oil water and eggs in a large bowl on low speed until moistened. Beat on medium speed for 2 minutes. Remove 1 1/2 cups batter; set aside. Beat ditched cocoa mix into remaining batter n low speed until blended. Pour into a pan. Drop reserved white batter randomly in 6cto 8 mounds onto batter in the pan. Cut through batter with knife for swirled effect.
Bake 40-45 minutes or until toothpick inserted in center comes out clean. Cool10 minutes and then remove from pan. Cool completely on a wire track.