Step 1: Preheat your oven to 350°F (175°C). Lightly grease and flour a 9x5-inch loaf pan, or line with parchment paper leaving an overhang on the sides.
Step 2: In a large bowl, thoroughly mash the ripe bananas with a fork until mostly smooth but with a few small lumps remaining for texture.
Step 3: Add the melted butter, granulated sugar, egg, and vanilla extract to the mashed bananas. Whisk until well combined.
Step 4: In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt.
Step 5: Gradually add the dry ingredients to the wet ingredients, mixing with a spatula or wooden spoon just until combined. Be careful not to overmix; a few streaks of flour are okay. If using, fold in chocolate chips or nuts at this stage.
Step 6: Pour the batter into the prepared loaf pan and spread evenly.
Step 7: Bake for 55-65 minutes, or until a wooden skewer or toothpick inserted into the center of the loaf comes out clean or with moist crumbs attached. If the top browns too quickly, you can loosely tent it with foil.
Step 8: Remove the loaf from the oven and let it cool in the pan for 10-15 minutes before carefully lifting it out onto a wire rack to cool completely. Slice and serve warm or at room temperature.