1. Preheat your oven to 350°F (175°C). Grease a 4x8-inch loaf pan.
2. In a mixing bowl, mash the ripe bananas with a fork until smooth.
3. Stir the melted butter into the mashed bananas.
4. Mix in the baking soda and salt.
5. Stir in the sugar, beaten egg, and vanilla extract.
6. Mix in the flour until just combined. Be careful not to overmix; a few lumps are okay.
7. Pour the batter into the greased loaf pan.
8. Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
9. Allow the banana bread to cool in the pan for 10 minutes, then remove it from the pan and transfer it to a wire rack to cool completely before slicing.