In a medium bowl, stir together flour, baking powder, soda, and salt. Set aside.
In a mixer bowl beat sugar and shortening with an electric mixer until light, scraping sides of the bowl often. Add eggs, one at a time, and the milk, beating until smooth after each addition. Add flour mixture and banana alternately to creamed mixture, beating till smooth after each addition. Fold in nuts, if using. You can always add chocolate chips or raisins, if you like.
Turn batter into a lightly greased 8x4x2-inch loaf pan. Bake in a 350 degree oven for 60 to 65 minutes or until a wooden pick inserted near center comes out clean. Cool in pan 10 minutes. Remove from pan; cool. For easier slicing, wrap in aluminum foil and place in a zip-lock bag and store overnight. Makes 1 loaf.