Set oven to 325 degrees. Spray and line a 9x5 inch loaf pan with parchment paper with long ends. Whisk the flour, salt, baking powder, baking soda, cinnamon, and sugar together in a large mixing bowl or stand mixer.
Beat in the egg, oil, and vanilla.
Fold in the banana and nuts (if desired). Combine well, then turn the batter evenly into the pan. Bake for about an hour or more until a toothpick inserted in the center comes out clean. Let the bread cool for about 15 minutes in the pan, then remove to a rack to cool completely before frosting.
Blend the cream cheese, sugar, and vanilla with enough milk to make it spreadable. Spread over top of cooled bread and sprinkle with chopped walnuts.
Recipe by The Gingham Apron at https://www.theginghamapron.com/banana-bread-with-cream-cheese-frosting/