Preheat oven to 375 F. Line muffin tin with cupcake papers.
In a large bowl, sift together flour, sugar, Clabber Girl Baking Powder and salt. Add shortening, bananas, evaporated milk, vanilla, and eggs all at once. Beat on medium until blended, then beat 3 minutes longer. Stir in chocolate chips. Pour batter into prepared muffin cups, filling about 3/4 full.
Bake 20 minutes or until a toothpick inserted in center comes out clean. Remove from pan. Cool on wire rack.
In a small bowl, combine margarine, evaporated milk, and banana flavoring. Add powdered sugar, 1 cup at a time, mixing until smooth after each addition. Mix until frosting is smooth and shiny. If consistency is too thick, add a few drops of evaporated milk.
Frost cupcakes and sprinkle with chocolate chips