Preheat the oven to 350ºF. Grease a 9×5-inch loaf pan with nonstick cooking spray and set aside.
In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large bowl, mash the ripe bananas with a fork. Add the peanut butter and melted butter and stir until combined. Stir in the brown sugar, egg, and vanilla extract. Stir until smooth.
Stir the dry ingredients into the wet ingredients, don’t over mix.
Pour batter into prepared pan. Bake for 50-65 minutes, or until a toothpick inserted into the center of the bread comes out clean. Check the bread at 50 minutes, just to be safe. Oven times vary.
Remove the pan from the oven and set on a wire cooling rack. Let the bread cool in the pan for 10 minutes. Run a knife around the edges of the bread and carefully remove from the pan. Let the bread cool on the wire cooling rack until slightly warm. Cut into slices and serve.Note-the bread will keep on the counter, wrapped in plastic wrap, for up to 3 days. This bread also freezes well. To freeze, cool the bread completely and wrap in plastic wrap and place in a freezer bag. Freeze for up to 1 month. Defrost before slicing.