Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking pan lined with parchment paper.

Grate one medium zucchini, then squeeze in a clean kitchen towel to remove excess moisture.

In a large mixing bowl, whisk together melted unsalted butter and packed brown sugar until smooth. Add eggs one at a time, then stir in vanilla extract.

Sift in the flour, cocoa powder, baking soda, and salt. Fold gently to combine without overmixing.

Fold the squeezed-dry zucchini and chocolate chips into the batter.

Pour the batter into the prepared pan and bake for 20-25 minutes, checking doneness with a toothpick.

Let the brownies cool in the pan for 10-15 minutes before lifting them out to cool completely on a wire rack.