Preheat oven to 350 degrees F. Line a 12-cup muffin tin with silicone re-useable muffin cups.
In a medium bowl, combine flour, baking powder, cinnamon and salt.
1.5 cup gluten-free flour, ½ teaspoon baking powder, 1 teaspoon cinnamon, ½ teaspoon salt
In a separate bowl, hand beat the egg and combine with the applesauce, banana, milk, grated zucchini. Then grate lemon zest over top.
1 egg, ½ cup unsweetened apple sauce, ½ cup mashed banana (about ½ medium banana), 2 tablespoon 2% milk, 1 cup grated zucchini, 2 teaspoon grated lemon zest
Add wet ingredients to the dry ingredients and stir until almost combined. Do not over-mix (makes for a tough muffin.)
Add chocolate chips and stir one last time.
¼ cup dark chocolate chips (optional)
Divide mixture between 12 muffin cups, about 2 tablespoon each cup.
Bake in a preheated oven for 15-17 minutes or until inserted toothpick comes out clean.