Preheat oven to 350 degrees F. Grease a 9×5” loaf pan. In a medium-large bowl. Combine 1½ C shredded zucchini, ½ C plain greek yogurt or sour cream, 1/3 C brown sugar, 1/4 C white sugar, 2 eggs, 1 tsp vanilla and mix well. Add 1 C flour, ½ C cocoa powder, 1 tsp baking soda, ¼ tsp baking powder, ½ tsp salt and mix until all ingredients are incorporated. Stir in 1 C chocolate chips (milk or semi-sweet).
Transfer batter to prepared bread pan and bake for 55-65 minutes until a toothpick inserted in the centre of the loaf comes out “dry”. Allow to cool completely, then gently run a knife around the edge of the pan to loosen the bread and remove it from the pan. Melt ¼ cup chocolate chips in a small bowl in the microwave and drizzle on top of the loaf. Slice and serve.
If you would like to make muffins, you can make 12 large muffins and cook for 20-25 minutes until a toothpick inserted in the centre comes out clean.