Preheat to 350°F (175°C). Grease a 9×5-inch loaf pan or line with parchment paper.
Mash 3 large bananas in a large bowl until mostly smooth. Small lumps are fine.
Stir in melted 1/3 cup unsalted butter, 2 large eggs 1/2 cup granulated sugar , 1/4 cup brown sugar , and 1 teaspoon vanilla extract until combined.
Fold in 1 1/2 cups all-purpose flour, 1 teaspoon baking soda, and 1/2 teaspoon salt Mix gently until just combined; don’t overmix.
Fold in chocolate chips or 1/2 cup chopped nutsif desired.
Transfer batter to prepared loaf pan and smooth the top evenly.
Bake 55–65 minutes. Insert a toothpick in the center—if it comes out clean (a few melted chocolate streaks are fine), it’s done.
Let bread cool in pan 10–15 minutes. Transfer to a wire rack to cool completely before slicing.
Slice and enjoy as is or with butter, cream cheese, or nut butter.