Preheat oven to 350°F. Lightly grease a 9x5-inch loaf pan with butter or cooking spray.
In a large mixing bowl, mash the bananas with a fork until smooth. Stir in the sugar, egg, melted butter, and vanilla extract.
In another bowl, whisk together the flour, baking powder, baking soda, and salt.
Add the dry ingredients to the wet banana mixture and mix until combined.
Pour the batter into the prepared loaf pan. Bake for 50 minutes to 1 hour or until a toothpick inserted into center of the loaf comes out clean.
Remove from oven and let cool in the pan for a few minutes. Then remove the banana bread from the pan and allow it to cool completely before slicing and serving.
Notes
You can store banana bread at room temperature for 3 to 5 days or in the freezer for up to 3 to 4 months.