Preheat oven to 350 degrees F. Prepare a 12-tin muffin pan with paper liners.
Add all dry ingredients to a large bowl and whisk to combine.
In a medium bowl whisk together wet ingredients then stir in zucchini until well combined.
Add wet ingredients to dry ingredients and mix until just combined. Transfer batter evenly between muffin tins. Top with extra chocolate chips.
Bake 18-20 minutes, until a toothpick inserted in a center muffin comes out just clean. Start checking around 17 minutes to avoid overbaking. Tops brown quickly.
Notes
Don't overbake. These muffins brown quickly in the last few minutes, so I highly recommend starting to check them at 17 minutes for doneness to avoid over baking. They should be done between 18-20 minutes,