Preheat your oven to 350°F (175°C). Prepare a 9x5-inch loaf pan by greasing it with butter or lining it with parchment paper.

In a large mixing bowl, mash overripe bananas until smooth. Add melted unsalted butter, granulated sugar, brown sugar, large egg, and vanilla extract; stir until creamy.

In a separate bowl, whisk together all-purpose flour, baking soda, and salt.

Fold the dry ingredients into the wet banana mixture using a spatula until just combined. If desired, fold in chocolate chips or nuts.

Pour the batter into the prepared loaf pan and smooth the top. Bake for 55 to 65 minutes. Check for doneness with a skewer.

Let the banana bread cool in the pan for 10 to 15 minutes, then transfer to a wire rack to cool completely.