Prepare the Cake or Cupcakes: Heat the oven to 325°F. In a large mixing bowl combine the flour, cocoa, baking soda, baking powder, cinnamon, cloves, and a pinch of salt; mix with a fork and set aside.
n a food processor, process the eggs, sugar, and vanilla until fluffy, then add the butter. Process about 1 minute. With the machine running, add the milk and oil. Stop the machine and add the zucchini; plus until mixed; add the dry ingredients and process, with pulses, until the flour disappears. Do not over process.
Pour into greased and floured cake rounds (tip: use cocoa powder to flour your pan, it adds more flavor and better color) Or, ladle into a muffin tin that has paper inserts; fill about ¾ full.
Bake for 40 - 45 minutes (for the cake) or 25 minutes (for cupcakes); or until a toothpick inserted into the middle comes out clean. Allow to cool then frost.
Prepare the Frosting: In a small pan heat the butter and evaporated milk. Chop the semi-sweet chips in the food processor; with the machine running add the hot milk mixture. Add powdered sugar to make a spreadable consistency. Spread on the top of the cake; sprinkle with nuts, if desired.