Preheat the oven to 375F. Grease or line a standard 12 cup muffin tin. Set aside.
Add the mashed banana and melted butter to a large mixing bowl, and mix until combined.
1 ½ cups mashed ripe banana, ½ cup salted butter
Stir in the egg, maple syrup, and vanilla extract until combined.
1 large egg, ½ cup pure maple syrup, ½ teaspoon vanilla extract
Add the all purpose flour, cinnamon, baking soda and salt. Stir in just until combined.
1 ½ cups sifted all-purpose flour, 1 teaspoon ground cinnamon, 1 ½ teaspoons baking soda, 1/4 teaspoon salt
Divide the batter between the prepared muffin tins, filling about 2/3 full.
Bake for about 15-25 minutes or until a toothpick can be inserted and comes out clean.
Let the muffins cool in the pan for about 5 minutes before moving to a wire cooling rack to cool.
Notes
Bananas: I like to use overripe bananas that are part yellow, part brown spots.
Butter: If using unsalted butter, increase the salt to 1/2 teaspoon.
Maple syrup: I recommend using pure maple syrup. For stronger maple flavor, you can add up to 1 teaspoon of maple extract along with the vanilla extract.