Preheat and Prepare: Preheat your oven to 350 F (175 C). Lightly grease and flour a 9x5-inch loaf pan.
Combine Wet Ingredients: In a large bowl, mash the ripe bananas with a fork until they are mostly smooth with a few small lumps. Stir in the melted butter, sugar, beaten egg, and vanilla extract until well combined.
Mix Dry Ingredients: In a separate medium bowl, whisk together the flour, baking soda, and salt.
Combine All Ingredients: Add the dry ingredients to the banana mixture and stir with a spoon or spatula just until the flour disappears. Do not overmix. Overmixing can lead to a tough, dense bread. If you're using nuts or chocolate chips, gently fold them in now.
Bake: Pour the batter into your prepared loaf pan and smooth the top. Bake for 55 to 65 minutes, or until a toothpick or wooden skewer inserted into the center comes out clean.
Cool: Let the banana bread cool in the pan for about 10 minutes before turning it out onto a wire rack to cool completely. Slicing it while still warm can make it crumbly.