Preheat the oven to 350F degrees and line a 9-inch square baking pan with parchment paper and set aside.
Add the diced zucchini, vegetable oil, eggs, and vanilla to a food processor or blender and blend until smooth.
Pour the mixture into a large mixing bowl or stand mixer bowl.In a separate bowl, whisk together the flour, sugar, cocoa, baking powder, and salt - add the dry ingredients to the wet ingredients and mix just until combined.
Fold in the chocolate chips and pour the batter into the prepared baking pan.
Bake for 25 to 30 minutes. Remove from the oven and allow to cool for about an hour then top with frosting (if using.) Slice and serve.