Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper for easier removal.
In a bowl, grate the zucchini using a box grater, then squeeze out excess water using a clean kitchen towel. Set aside.
In a medium mixing bowl, whisk together the all-purpose flour, whole wheat flour, baking powder, baking soda, salt, and ground cinnamon.
In a large bowl, combine granulated sugar, brown sugar, and vegetable oil. Mix until well combined.
Add the eggs one at a time, mixing thoroughly after each addition, then stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Fold in the grated zucchini, chocolate chips, and chopped walnuts (if using) into the batter until evenly distributed.
Pour the batter into the prepared loaf pan and spread it evenly.
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted in the center comes out clean.
Once done, let the bread cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Notes
Slice the bread and serve warm with a pat of butter on top. For an added touch, sprinkle some chocolate chips on top before baking for an enticing look!