Preheat the oven to 350ºF with a rack in the middle. Butter a loaf pan.
In a large bowl, cream together the bananas, cream cheese and sugar until smooth. Mix in the butter.
In a separate bowl, combine the salt, baking powder and flour. Slowly mix the flour mixture into the banana mixture. Whisk in the vanilla. Scrape the mixture into the pan.
In a small bowl, combine the brown sugar and cinnamon. Sprinkle the mixture evenly over the top of the dough.
Bake for about 45 minutes or until an inserted toothpick comes out clean. Allow the bread to cool before removing from the pan.