How to Make It
Preheat oven to 350°F. Spray an 8 1/2- x 4 1/2-inch baking pan with cooking spray.
Whisk together mashed bananas, sugar, melted butter, egg, and vanilla in a large bowl until well combined.
Stir together flour, baking soda, and salt in a medium bowl. Add flour mixture to banana mixture, stirring until combined. Pour batter into prepared pan.
Bake in preheated oven until golden brown and a wooden pick inserted in center comes out clean, 50 to 60 minutes. Let cool in pan 5 minutes. Remove from pan, and cool completely on a wire rack.