Preheat the oven to 350°F (175°C).
Grease a 4x8-inch bread loaf pan. Make sure to verify that your pan sizing is correct.
In a medium to large size mixing bowl, mash the ripe bananas until smooth. Add melted butter into the mashed bananas and stir to combine.
Stir in the sugar, egg, and vanilla extract.
Add in the flour, baking soda and salt. Mix until combined but take care not to over-mix.
Pour the batter into your prepared baking pan.
Bake for 50 minutes to 60 minutes or until a toothpick inserted into the center of the bread comes out clean. If you are worried about bread over browning towards the end, you can loosely place a piece of aluminum foil over the bread.
Remove from oven and let cool in the pan for approximately ten minutes. Then remove the banana bread from the pan and let cool completely on a wire cooling rack.