Preheat oven to 350F. Grease or spray a 9 inch loaf pan, set aside.In a large bowl whisk together the melted butter, and sugars. Add the eggs one and a time and vanilla and whisk until smooth.Sprinkle the flour, baking soda and salt over the butter mixture and stir to mix until just combined. Fold in the bananas and sour cream.Pour batter into prepared pan and bake 60 minutes or until crust is golden brown and a toothpick inserted into the center comes out clean. Cool until warm before serving.