Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan with cooking spray or butter, or line it with parchment paper for easy removal.
In a large mixing bowl, combine the grated zucchini, granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract. Stir vigorously until all ingredients are well blended and the mixture is smooth.
In another bowl, whisk together the all-purpose flour, cocoa powder, baking soda, baking powder, and salt until they are evenly combined.
Gradually add the dry mixture to the wet zucchini mixture, stirring gently until just incorporated. Be cautious not to overmix; a few small lumps are perfectly fine.
Carefully fold in the semi-sweet chocolate chips, white chocolate chips, and dark chocolate chunks, ensuring they are evenly dispersed throughout the batter.
Pour the prepared batter into the greased or lined loaf pan, using a spatula to smooth the surface and ensure an even top.
Bake in the preheated oven for 50-60 minutes. To check for doneness, insert a toothpick into the center of the bread; it should come out clean or with a few moist crumbs.
Once baked, let the zucchini bread cool in the pan for about 10 minutes. Then gently transfer it to a wire rack to cool completely, allowing air to circulate around the loaf.
Notes
For an elegant touch, slice the bread and arrange it artfully on a rustic wooden board, lightly dusted with powdered sugar.