Step 1

Preheat the oven to 350°F. Spray a 9x13-inch baking dish with cooking spray or lining with parchment paper.

Step 2

In the bowl of a stand mixer fitted with the paddle attachment, mix 1 1/2 cups sugar, 1/2 cup oil, and 2 teaspoons vanilla over medium speed until well combined.

Step 3

In a medium bowl, whisk together 2 cups flour, 1/2 cup cocoa powder, 1 1/2 teaspoons baking soda, and 1 teaspoon salt until combined.

Step 4

Mix the dry ingredients into the wet ingredients until just combined. It will be crumbly. Once you start stirring in the zucchini, the zucchini itself adds all the moisture needed.

Step 5

Fold in 2 1/2 cups zucchini and 1 cup chocolate chips and mix until batter is smooth. Spread the batter in an even layer in the baking dish. Sprinkle a few extra chocolate chips on top.

Step 6

Bake 25 to 30 minutes, or until the top is dry and edges have started to pull away from the sides. Let cool 20 minutes.