
Preheat your oven to 350°F. Line a standard muffin pan with paper liners and set aside.
In a large mixing bowl, mash the ripe bananas until smooth. Add the granulated sugar and eggs, then whisk until well combined.
Stir in the melted butter and vanilla extract until fully incorporated.
In a separate bowl, whisk together the sifted flour, baking soda, baking powder, cinnamon, and nutmeg.
Gradually add the dry ingredients to the banana mixture, stirring just until combined. Avoid overmixing — a few small lumps are completely fine.
Divide the batter evenly among the prepared muffin liners, filling each about ¾ full.
Bake for 20 to 25 minutes, or until a toothpick inserted into the center comes out clean.
Let the muffins cool in the pan for about 5 minutes, then transfer them to a wire rack to cool completely before serving.