Preheat oven to 175°C (350°F) and grease a 4x8 inch loaf pan.
In a large mixing bowl, combine mashed bananas with melted butter.
Add sugar, beaten egg, vanilla extract, cinnamon, and salt; whisk until smooth.
Incorporate baking soda into the wet mixture.
Gently fold in the flour using a spatula until no dry streaks remain, ensuring the batter is not over-aerated.
Transfer the batter to the prepared loaf pan and level the surface.
Bake for 55 to 60 minutes, or until a skewer inserted into the center of the loaf comes out clean.
Allow the loaf to cool in the pan for 10 minutes before transferring to a wire rack for complete cooling.