Step 1
Preheat oven to 350°F. Grease and flour one (1-pound) loaf pan.
Step 2
In a medium bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt.
Step 3
In a large bowl, mix sugar, vegetable oil, egg, milk, and vanilla until well combined. Add the grated zucchini and mix. Using a spatula, gently add the flour mixture to the zucchini mixture and mix until incorporated and no dry flour remains. Add chocolate chips and mix.
Step 4
Pour mixture onto prepared pan and bake for 50-55 minutes or until a toothpick inserted in the center of the bread comes out clean. Allow the bread to cool in the pan for 5 minutes and then carefully remove from pan; cool over a cooling rack.
The same amount of batter makes six large muffins. Adjust baking time to 30 minutes.