Step 1

Preheat oven to 350 degrees. Line 9 1/2"x13" baking pan {1/4 sheet pan size} with parchment paper, lightly spray with nonstick cooking spray, and set aside.

Step 2

In a medium saucepan, melt the oil, chocolate chips, and cocoa together over medium-low heat. Remove from heat and stir in sugar, eggs, vanilla, and zucchini. Stir in dry ingredients, then pour into prepared pan. Spread out evenly and bake 15-20 minutes or until a toothpick comes out clean when inserted in the middle. {A few moist crumbs is fine.}

Step 3

While brownies are baking, melt butter, cocoa powder, chocolate chips, and milk together and simmer gently 1 minute. Remove from heat, then whisk in vanilla and powdered sugar.

Step 4

Once brownies are pulled from the oven, pour hot frosting over bars immediately. Spread to smooth, if needed. Cool 5-10 minutes before cutting into pieces and serving.