Sift together the flour, baking powder, baking soda, salt, and sugar.
Add shortening, eggs, chopped nuts, and mashed bananas.
Beat until ingredients are blended, about 1 minute. Scrape the bowl while beating. Pour batter into a greased loaf pan.
Bake at 350°F for about 1 hour or until done. Makes 1 medium-sized loaf.