Preheat oven to 350°F (175°C).
Grease a 9 × 5-inch loaf pan and line with parchment paper.
Mash the ripe bananas directly in a large mixing bowl.
Whisk in the melted butter.
Add brown sugar and granulated sugar and whisk to combine.
Add eggs and vanilla and whisk until incorporated.
Add flour, baking soda, cinnamon, and salt directly to the bowl.
Fold gently with a spatula until just combined.
Fold in optional walnuts, pecans, or chocolate chips.
Transfer the batter to the prepared loaf pan.
Add the optional lengthwise banana topping.
Bake for approximately 55–65 minutes.
Check the center with a wooden skewer or toothpick.
Loosely cover with foil if the top browns before the center is finished.
Cool in the pan for approximately 15 minutes.
Remove and transfer to a wire rack.
Allow to cool substantially before slicing.