01 - Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line with parchment paper.
02 - In a medium bowl, whisk together all-purpose flour, baking soda, and salt until well blended.
03 - In a large bowl, mix melted butter with granulated sugar until smooth. Beat in eggs one at a time, then stir in vanilla extract and mashed bananas.
04 - Gradually add dry mixture to wet ingredients and stir until just combined. Do not overmix. Fold in walnuts, if using.
05 - Spread the batter evenly in the prepared loaf pan.
06 - Bake in preheated oven for 55 to 65 minutes, or until a toothpick inserted into the center comes out clean.
07 - Allow bread to cool in pan for 10 minutes before turning out onto a wire rack to cool completely. Slice and serve.