Preheat oven to 425F (220C) and line a 12-count muffin tin with paper liners. Set aside.

In a large mixing bowl, combine sugars, oil, milk, egg, and vanilla and whisk vigorously until mixture is very well-combined and uniform in texture.

In a separate, medium-sized mixing bowl whisk together flour, baking powder, cinnamon (if using) and salt.

Add the wet ingredients to the dry and use a spatula to gently fold together until about 50% combined. Add blotted zucchini and chocolate chips and continue to stir gently until batter is mostly uniform and zucchini and chocolate are well distributed.

Evenly divide batter into prepared muffin tin.

Sprinkle muffin tops with additional sugar, then transfer to center rack of 425F (220C) oven. Bake for 8 minutes, then, without opening the oven door, reduce the oven temperature to 350F and continue to bake another 8-10 minutes, until muffins are baked through and a toothpick inserted in the center comes out clean or with a few moist crumbs.

Allow muffins to cool in the tin for 5-10 minutes before carefully removing to a cooling rack to cool further before enjoying.