Grease a 9x5" loaf-pan. I also like parchment paper for the bottom to prevent the loaf from sticking to the pan). Mash bananas in a mixing-bowl. Add egg, brown sugar, vanilla, cinnamon and granulated-sugar together. Stir well to combine.
In a small bowl combine flour, salt, baking powder and baking soda. Add to banana mixture and stir to combine. Gently stir in melted butter and bake at 350°F for 35-45 mins or till a toothpick inserted in the middle comes out clean.
Let the pan cool for between 5-10 minutes, before inverting onto a wire cooling rack.