01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or grease lightly with cooking spray.
02 - In a large mixing bowl, whisk together mashed bananas, eggs, oil, brown sugar, milk, and vanilla extract until smooth and fully incorporated.
03 - In a separate medium bowl, sift together flour, baking soda, baking powder, cinnamon, and salt to ensure even distribution.
04 - Gradually fold the dry mixture into the wet ingredients using a spatula. Stop mixing as soon as the flour disappears—small lumps are acceptable and prevent tough muffins.
05 - Gently fold in the chocolate chips, reserving about 1 tablespoon to sprinkle on tops before baking.
06 - Divide batter evenly among the 12 muffin cups, filling each about three-quarters full. Top with reserved chocolate chips.
07 - Bake for 18 to 22 minutes until a toothpick inserted into the center comes out clean or with just a few moist crumbs.
08 - Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.