Preheat your oven to 350°F (175°C). Grease a 9×9-inch baking pan or line it with parchment paper.
In a large bowl, whisk together the flour, cocoa powder, baking powder, and salt.
In another bowl, combine the granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract. Mix until smooth.
Stir in the shredded zucchini, ensuring it’s evenly distributed throughout the wet ingredients.
Gradually add the dry ingredients to the wet mixture, stirring just until combined. Be careful not to overmix.
Gently fold in the mini chocolate chips and semisweet chocolate chips.
Pour the brownie batter into the prepared pan and spread it evenly.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs (not wet batter). Let the brownies cool completely in the pan before cutting them into squares.
For an extra touch, drizzle melted butter and a bit of milk over the top before serving for a glossy, chocolate finish.