Zucchini adds texture–and nutrition–to this traditional dessert.
Preheat oven to 325°F. In a large bowl, cream together the margarine, oil, and sugar. Add the eggs, vanilla, and sour milk, and beat until well blended. In a separate bowl, mix the flour, cocoa, baking powder, baking soda, cinnamon, cloves, and zucchini. Add the dry ingredients to the egg mixture, and stir until well blended. Spread batter into a greased and floured 13x9-inch pan, and sprinkle with chocolate chips. Bake for 40 to 45 minutes.