1- Preheat the oven to 425°F (220°C). Prepare a muffin tin with nonstick spray or liners to prevent sticking and ensure easy removal.

2- In a medium bowl, whisk together 1 and 1/2 cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon baking soda, 1/2 teaspoon salt, 1 teaspoon ground cinnamon, and 1/4 teaspoon ground nutmeg until well combined.

3- In a large bowl or mixer, mash 1 and 1/2 cups bananas thoroughly. Beat in 6 tablespoons melted unsalted butter, 2/3 cup packed brown sugar, 1 large egg, 1 teaspoon pure vanilla extract, and 2 tablespoons milk until the mixture is smooth and blended.

4- Add the dry ingredients to the wet ingredients and mix until just combined to keep the batter light. Fold in 1 cup chopped walnuts, pecans, or chocolate chips if you’re using them for extra texture.

5- Spoon the batter into the muffin liners, filling them to the top for the best rise and a full, rounded shape.

6- Bake at 425°F for 5 minutes, then reduce the oven temperature to 350°F and bake for an additional 16-18 minutes, or until a toothpick inserted into the center comes out clean. For mini muffins, bake at 350°F for 12-14 minutes without the initial high heat.

7- Allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely, helping them set without becoming soggy.