Prep the oven and pan: Heat the oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease.
Grate the veggies: Finely shred zucchini and carrot. Place zucchini in a clean towel and gently squeeze to remove excess water.
Don’t over-squeeze; you still want moisture.
Mix the wet ingredients: In a large bowl, whisk banana, eggs, applesauce, maple syrup, vanilla, and oil until smooth.
Whisk the dry: In a separate bowl, combine flour, baking powder, baking soda, cinnamon, and salt.
Combine: Add dry ingredients to wet and stir just until a few streaks of flour remain. Fold in zucchini, carrot, and any optional mix-ins. Do not overmix.
Fill the cups: Divide batter evenly among the muffin cups, filling about 3/4 full.
Bake: Bake 16–20 minutes, until the tops are set and a toothpick comes out clean or with a few moist crumbs.
Cool: Let muffins rest in the pan for 5 minutes, then move to a rack to cool completely.
This helps them set and stay tender.