Preheat the oven to 350 degrees.

Line 2 muffin tins with 18 cupcake liners. I usually fill the outside of the tins first and leave the middle of the tins empty.

In a medium bowl combine the flour, baking soda, baking powder, salt, and cinnamon. Mix and set aside.

In a large bowl mix together the melted butter and brown sugar.

Add in the eggs and vanilla and mix well.

Add the flour mixture to the butter mixture and mix until just starting to combine.

Stir in the zucchini and chocolate chip sand mix until just combined.

Divide the batter between the muffin cups filling almost to the top.

Bake for 20-22 minutes or until a toothpick inserted into the center comes out clean.

Remove from oven and cool on a wire rack.