Preheat your oven to 400°F (200°C). Line a 12-cup muffin tin with paper liners. Lightly spray the liners with non-stick cooking spray for extra easy removal, especially if not using paper liners.

In a large mixing bowl, whisk together the all-purpose flour, baking soda, baking powder, ground cinnamon (if using), and salt until well combined. Set aside.

In a separate medium mixing bowl, mash the ripe bananas with a fork until mostly smooth but still with a few small lumps for texture. Add the granulated sugar, brown sugar, melted butter, egg, vanilla extract, and milk to the mashed bananas. Whisk until just combined. Do not overmix.

Pour the wet banana mixture into the dry ingredients. Using a spatula, gently fold the ingredients together until just combined. Be careful not to overmix; a few lumps of flour are fine. Overmixing will result in tough muffins. If using, gently fold in chocolate chips or nuts.

Divide the batter evenly among the 12 prepared muffin cups, filling each about two-thirds full.

Bake for 5 minutes at 400°F (200°C). This initial high heat helps create a beautiful domed top. Then, reduce the oven temperature to 375°F (190°C) and continue baking for another 13-15 minutes, or until a wooden skewer inserted into the center of a muffin comes out clean or with moist crumbs, but no wet batter.

Remove the muffin tin from the oven and let the muffins cool in the tin for 5 minutes before transferring them to a wire rack to cool completely. Enjoy warm or at room temperature.