Preheat your oven to 350°F (175°C) and grease a 9×9-inch baking pan or line it with parchment paper.

Grate the zucchini using a box grater and then squeeze it in a clean kitchen towel to remove excess moisture.

In a large bowl, whisk together the melted butter and sugar until combined. Add in the eggs and vanilla extract, mixing well until creamy.

In another bowl, mix the flour, cocoa powder, baking powder, baking soda, and salt. Gradually add this to the wet mixture, stirring until just combined.

Fold in the grated zucchini and chocolate chips (if using) until evenly distributed throughout the batter.

Pour the brownie batter into your prepared baking pan and spread it evenly.

Bake for about 25-30 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.

Allow the brownies to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.

Once cooled, slice into squares and enjoy!