Preheat oven to 350°F. Line a 12-count muffin tin with paper liners. Set aside.
In a medium-sized bowl, whisk the mashed bananas, sugar, melted butter, vanilla extract, and eggs together.
¾ cup overripe bananas, ¾ cup granulated sugar, ½ cup salted butter, 2 teaspoons pure vanilla extract, 2 large eggs
Over the wet ingredients, sprinkle on the flour, baking soda, cinnamon, nutmeg, salt, and walnuts. Stir until incorporated. Do not over mix.
2 cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon ground cinnamon, 1 teaspoon ground nutmeg, ½ teaspoon kosher salt, 1 cup chopped walnuts
Fill prepared muffin tin wells ⅔ full.
Bake for 25-30 minutes, or until a toothpick comes out clean and the muffins spring back when pressed.
Allow to cool in muffin tins for 5 minutes before transferring muffins to a cooling rack. Repeat if needed to use up all of the batter.