1) Preheat the oven to 350°F. Lightly grease an 8" square or 9" round pan; or line 12 muffin cups with cupcake papers, and spray the insides of the papers with non-stick vegetable oil spray.
2) Whisk together the baking mix and cocoa.
3) Beat the sugar, butter, vegetable oil, and vanilla together until well blended and lighter in color.
4) Add the eggs one at a time, mixing until just incorporated after each addition.
5) Stir in the baking mix alternately with the water.
6) Spread the batter into the prepared pan. For cupcakes, scoop batter by level 1/4 cupfuls into the prepared muffin tins; a muffin scoop works well here.
7) Bake the cake until a cake tester or toothpick comes out clean and the middle springs back when pressed lightly, 35 to 40 minutes for a layer, or 20 to 22 minutes for cupcakes.
8) Remove the cake from the oven, and set it on a rack. Allow it to cool for 5 to 10 minutes before removing it from pan.
9) Cool another 5 to 10 minutes before cutting into squares; or cool completely before frosting.
Yield: Yield: one 8" square cake, one 9" round cake, or 12 cupcakes.