In a large mixing bowl, whisk together the dry ingredients (flour, cocoa powder, baking powder, baking soda, salt and sugar). Add zucchini and stir to coat. Add chocolate chips and stir again.
In another mixing bowls, whisk together the wet ingredients (buttermilk, oil and egg). Add the wet ingredients to the dry ingredients and stir it all together with a wooden spoon or a spatula. Do not overmix.
Pour the batter into prepared loaf pan. Bake for 40 to 50 minutes OR until a toothpick inserted in few places in the bread comes out clean.
Cool the bread in pan for 10 minutes. Remove from pan onto a cooling rack or a cutting board. Cool completely before slicing.
Notes
It is very important to squeeze as much moisture from the shredded zucchini as possible. Use a stack of two paper towels or cheese cloth.To make homemade buttermilk: whisk 1 tablespoon of apple cider vinegar and enough half and half to make 1 cup of liquid. Let sit for 3 to 4 minutes. It should thicken and curdle.