Preheat Oven: Set your oven to 350°F (175°C).
Prepare the Pan: Grease a 9×5-inch loaf pan with nonstick spray or line it with parchment paper.
Mix Wet Ingredients: In a bowl, combine the mashed bananas, sugar, egg, mayonnaise (or Greek yogurt), and vanilla extract until smooth.
Combine Dry Ingredients: In a separate bowl, whisk together the flour, salt, and baking soda.
Mix Batter: Gradually add the dry ingredients to the wet mixture, stirring until just combined. If desired, fold in walnuts or chocolate chips.
Bake: Pour the batter into the prepared loaf pan. Bake for 55-60 minutes, or until a toothpick inserted into the center comes out clean.
Cool: Allow the bread to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.