Preheat your oven to 350°F (175°C).
In a mixing bowl, mash the ripe bananas until smooth.
Stir in the melted butter into the mashed bananas until blended.
Mix in the baking soda and salt.
Stir in the sugar, egg, and vanilla extract until well combined.
Add the flour and mix until just incorporated.
Fold in the chopped walnuts or pecans if using.
Pour the batter into a greased loaf pan.
Bake in the preheated oven for 60-65 minutes.
Let the banana bread cool in the pan for about 10 minutes before transferring.