Preheat your oven to 350°F (175°C).
In a mixing bowl, mash the ripe bananas with a fork.
Add the melted butter to the mashed bananas and mix well.
Stir in the baking soda and salt.
Add the sugar, beaten egg, and vanilla extract, mixing until combined.
Gradually add the flour and stir until just incorporated.
Fold in the chopped walnuts gently.
Pour the batter into a greased loaf pan.
Bake for 60 minutes or until a toothpick inserted comes out clean.
Allow cooling in the pan for 10 minutes, then transfer to a wire rack to cool completely.