Set the oven to 350°F and let it heat up while preparing the batter.
Place 12 muffin liners in a standard muffin tin. If liners are unavailable, lightly grease each muffin cup with butter or non-stick spray.
In a large mixing bowl, mash the overripe bananas until smooth. A fork or a potato masher works well for this.
Whisk the eggs into the mashed bananas until the mixture is smooth and well blended.
Mix in the light brown sugar, ground cinnamon, and a pinch of sea salt.
Stir in the pure vanilla extract, whole milk, and melted butter until fully incorporated.
Gradually sift in the all-purpose flour and baking powder, gently folding the mixture until combined. Be careful not to overmix; the batter should be slightly lumpy.
Stir in the milk chocolate chips until they are evenly distributed throughout the batter.
Using a spoon or a cookie scoop, divide the batter into the 12 muffin cups. Each cup should be about three-quarters full.
In a small bowl, combine the ground cinnamon and granulated sugar. Sprinkle the cinnamon-sugar mixture generously over the top of each muffin.
Place the muffin tin in the preheated oven and bake for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes. Then transfer the muffins to a wire rack to cool completely.
Notes
Storage Tips
At room temperature: Store the muffins in an airtight container at room temperature for up to 3 days.
In freezer: For longer storage, freeze the muffins in a zip-top bag for up to 3 months. To enjoy, thaw at in the fridge or warm in the microwave.