Preheat oven to 350.
Spray a loaf pan with non stick spray and set aside.
In a small bowl, combine flour, baking soda, cinnamon and salt. Set aside.
In a large bowl (or stand mixer) beat sugar and eggs 2 minutes. Add melted butter, bananas, sour cream and vanilla and beat again on medium speed 2 minutes more.
Gently fold the flour mixture into the wet ingredients. Stir until just combined.
Pour mixture into prepared loaf pan and bake 50-60 minutes. Test for doneness with a toothpick.
Cool on wire rack before slicing.