01 - Preheat oven to 350°F. Line a standard 12-cup muffin tin with paper liners or lightly grease each cup.
02 - Place grated zucchini in a clean kitchen towel and squeeze out excess liquid.
03 - In a large mixing bowl, whisk together whole wheat flour, protein powder, baking soda, baking powder, cinnamon, and salt until uniformly combined.
04 - In a separate bowl, beat eggs. Stir in mashed banana, applesauce, oil, honey or maple syrup, and vanilla extract until smooth.
05 - Add wet ingredients to the dry mixture and gently stir until just incorporated. Fold in zucchini and any chosen mix-ins without overmixing.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full.
07 - Bake for 22–25 minutes, until a toothpick inserted in the center of a muffin comes out clean.
08 - Allow muffins to cool in tin for 5 minutes before transferring to a wire rack to cool completely.