Melt the butter, then add sugar, eggs, and vanilla.
Mix 1/2 cocoa powder & cinnamon to dry cake mix.
Add dry ingredients to butter mixture.
Add 1 cup milk, shredded zucchini, & chocolate chips.
Pour into a greased 9x13 baking pan.
Bake at 350 for 40-45 minutes or until toothpick inserted into center comes out clean.
Pour on cake while warm (not hot)