Preheat your oven to 350°F (175°C). Butter or line a 4x8-inch loaf pan with parchment paper, allowing some overhang for easy removal later.
In a large bowl, mash the ripe bananas with a fork until smooth. For a chunkier texture, leave some small pieces intact.
Stir the melted butter into the mashed bananas. Mix in the baking soda and salt.
Add sugar, beaten egg, and vanilla extract, stirring until well combined.
Add the flour, folding gently until just combined. When you still see a few streaks of flour, fold in any optional ingredients like nuts or chocolate chips.
Pour the batter into your prepared loaf pan and bake for 55-60 minutes. The bread is done when a toothpick inserted into the center comes out clean, with perhaps a few moist crumbs.
Allow to cool in the pan for 10 minutes, then remove to a wire rack to cool for an additional 10-15 minutes before slicing.