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; mix until combined.
Gradually add the flour, mixing just until incorporated.
Fold in the chopped walnuts gently.
Pour the batter into a greased loaf pan.
Bake for 60 minutes or until a toothpick comes out clean.
Let the bread cool in the pan for a few minutes, then transfer to a wire rack.