Preheat your oven to 350°F (175°C) and prepare your loaf pan by greasing it or lining it with parchment paper.
In a large bowl, combine the mashed bananas with melted butter. Stir until smooth.
Mix in granulated sugar, beaten egg, and vanilla extract until fully combined.
Sprinkle baking soda and salt over the mixture before folding in the flour.
Gently mix until just combined—be careful not to overmix!
Pour the batter into the prepared loaf pan and smooth out the top. Bake for about 55-65 minutes until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.