Preheat oven to 350F degrees and prepare muffin tins with cupcake liners.
In a large mixing bowl sift together dry ingredients including flour, baking soda, baking powder, salt, and cinnamon.
In a large bowl, add smashed bananas. Add eggs, sugar, oil, and stir until fully incorporated.
Add the dry ingredients to the wet ingredients and stir until just combined. Do not over mix.
Grate the zucchini. If you’re using an extra-large zucchini, you’ll want to remove the tough seeds first. Drain any excess liquid from the zucchini before adding it to the batter.
Scoop the batter filling each cupcake liner about 3/4 full.
Mix together the ingredients for the streusel topping and sprinkle over the top of the muffin batter. Add chocolate chips if desired.
Bake for 20-25 minutes, or until a toothpick inserted in the center comes out clean.