Mix together bananas, mayonnaise, egg, and vanilla in a large bowl.
Whisk together flour, sugar, baking soda, and salt in a medium bowl. Add to banana mixture and stir until just combined.
Bake for 60-70 minutes, or until a toothpick comes out clean.
Cool for 15 minutes in the pan, then remove and place on a cooling rack.
Cool completely. Slice and serve!
Notes
For a 8 ½ x 4 ½" pan, bake for 75 minutes. Don't overmix the batter.Use ripe bananas that are mashed well. Use a blender if necessary to achieve a smooth consistency.Always add the dry to the wet ingredients to avoid pockets of flour.Don't forget to grease the loaf pan.Banana Bread should be stored in an air tight container. It can be frozen for about 3-4 months, refrigerated for about 1 week, or left on the counter 2-3 days.