1. Preheat oven to 350º and lightly grease an 8x4x2 inch loaf pan.
2. In a small mixing bowl combine flour, baking powder, salt and baking soda; stir until evenly distributed and set aside.
3. With an electric mixer, cream shortening and sugar until light and fluffy, scraping the sides of the bowl often. Add milk and eggs one at a time; beating well between additions. When the mixture is smooth remove the mixer.
4. Add one third of the flour mixture to the butter mixture and fold in gently. You do not want to overmix the batter at this point. When the first third of the flour is incorporated, add the mashed bananas, fold gently.
5. Fold in alternately the remaining flour and bananas. If adding nuts gently fold them into the batter at this point.
6. Scrape batter into the prepared loaf pan and bake for 60-65 minutes or until a wooden toothpick comes out clean. Allow loaf to cool in pan for 10 minutes, and then remove it from pan and allow it to cool completely on a wire rack.
7. For best taste, wrap completely cooled loaf in foil or plastic wrap overnight. Your banana nut bread will slice easier the next day as well.