Preheat your oven to 350 degrees F, grease or line a 9x5 loaf pan, set aside.
In a large mixing bowl combine melted butter, sugar, eggs, and vanilla. Whisk well to combine. Mix in the mashed bananas.
In a separate mixing bowl combine the flour, cinnamon, salt, and baking soda. Slowly add the dry ingredients into the wet until incorporated, careful not to overmix. Pour the batter into the prepared loaf pan.
In a small mixing bowl combine the softened butter, granulated sugar, brown sugar, flour, and cinnamon. Mix together until combined. Sprinkle evenly over the batter.
Bake at 350 for 55-60 minutes, or until a toothpick inserted in the middle comes out clean. Allow to cool slightly before slicing. This is best served immediately, but will keep in an airtight container for 3-4 days or wrapped tightly in the freezer for 4-6 months!
Notes
*If the topping crumbles while slicing, chill the bread for a few minutes.