Butter and flour a 9x13 inch baking pan, or a bundt pan.
Sift together the flour, cocoa powder, baking soda, salt, cinnamon, and cloves into a medium bowl.
Beat the sugars, butter and oil (or applesauce) in a large bowl until well blended.
Add the eggs 1 at a time, beating well after each addition.
Add the vanilla extract and buttermilk.
Add in dry ingredients. Stir well.
Gently fold in grated zucchini.
Pour into prepared pan.
Sprinkle with chocolate chips (and nuts, if using).
Bake 45-50 minutes or until toothpick inserted into the center comes out clean.
Cool cake completely in pan.