Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan or line it with parchment paper for effortless removal.
In a medium bowl, mix the grated zucchini with a pinch of salt. Let it rest for 10 minutes to draw out excess moisture. Afterward, firmly squeeze the zucchini to remove the moisture and set it aside.
In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, baking powder, salt, and ground cinnamon until evenly blended. Set this mixture aside.
In a large mixing bowl, combine the granulated sugar, brown sugar, vegetable oil (or melted coconut oil), eggs, and vanilla extract. Use a whisk or mixer to blend the ingredients until smooth and well integrated.
Gradually add the dry ingredient mixture to the wet mixture, folding gently until just combined. Be careful not to overmix, as this can affect the texture of the bread.
Carefully fold in the grated zucchini along with the semi-sweet chocolate chips, white chocolate chips, and dark chocolate chunks, ensuring they are evenly distributed throughout the batter.
Pour the batter into the prepared loaf pan, smoothing the top with a spatula for an even surface.
Bake in the preheated oven for 45 to 55 minutes. Check for doneness by inserting a toothpick into the center; it should come out clean or with a few moist crumbs.
Once baked, remove the loaf from the oven and let it cool in the pan for 10 minutes. Afterward, carefully transfer it to a wire rack to cool completely.
Notes
For an extra touch of elegance, dust the top with powdered sugar before serving. Pair with whipped cream, or enjoy warm with a scoop of creamy vanilla ice cream.