Preheat oven to 350°F. Line a muffin tin with liners.
Gently wrap the shredded zucchini in a paper towel or a clean towel and squeeze out any excess water. Set aside. (I prefer to not peel the green skin off on my zucchini, but you certainly can. If you have a very large zucchini, remove any seeds before the grating.)
In a large bowl whisk the flour, cinnamon, baking powder, baking soda, and salt.
In a separate medium bowl, add the mashed bananas, sugar, eggs, oil, and vanilla. Stir well until fully combined.
Add the wet ingredients to the dry ingredients. Stir until just combined.
Fold in the shredded zucchini.
Add ⅓ cup of batter to each cupcake liner.
Bake for 22-26 minutes, or until an inserted toothpick is removed with some crumbs, but no wet batter. Tops should be rounded and golden brown.
Let muffins cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.
