Set oven to 350°F (175°C) and line an 8×8-inch baking dish with parchment paper.
Mix Wet Ingredients:
In a large bowl, whisk melted butter, brown sugar, and granulated sugar until smooth. Add the egg and vanilla, whisking to combine.
Combine Dry Ingredients:
In a separate bowl, whisk together flour, baking soda, baking powder, cinnamon, and salt.
Blend Batter:
Stir the dry ingredients into the wet mixture until just combined.
Add Zucchini & Chocolate Chips:
Fold in the drained zucchini and chocolate chips gently.
Bake:
Spread the batter evenly in the prepared dish. Bake for 25–30 minutes, or until golden brown and a toothpick inserted in the center comes out with a few moist crumbs.
Cool & Slice:
Allow to cool completely before slicing into 12 bars.
Tips & Variations
