Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan or line it with parchment paper.

In a large mixing bowl, whisk together the flour, cocoa powder, baking soda, baking powder, salt, and cinnamon. Set aside.

In a medium mixing bowl, beat together the sugar, oil, eggs, and vanilla extract until smooth. Stir in the grated zucchini.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

Fold in the chocolate chips (and nuts if using) until evenly distributed throughout the batter.

Pour the batter into the prepared loaf pan and smooth the top with a spatula. Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

Allow the bread to cool in the pan for about 10 minutes. Then, transfer it to a cooling rack to cool completely before slicing.

Slice the bread and enjoy it as a delicious snack, breakfast, or dessert. It’s especially good served warm with a spread of butter or a drizzle of honey.