In a small bowl, beat shortening and sugar until crumbly, about 2 minutes. Beat in egg yolks. Beat in banana on low speed until blended. Combine the flour, baking powder, salt and baking soda; add to banana mixture alternately with buttermilk, beating well after each addition. In a small bowl, beat egg whites until soft peaks form; fold into batter.
Coat two 6-in. round baking pans with cooking spray and dust with flour. Add batter. Bake at 375° for 23-25 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
For frosting, in a small bowl, beat shortening and butter until smooth. Add 1/2 cup confectioners' sugar, salt and extract; mix well. Stir in banana. Beat in enough of the remaining confectioners' sugar to achieve desired spreading consistency. Tint with food coloring if desired.
Spread between layers and over top and sides of cake. Store in the refrigerator.