Stir together flour, sugar, baking powder and salt. Set aside.
In large mixing bowl, combine KELLOGG'S ALL-BRAN cereal, milk and bananas. Let stand about 2 minutes or until cereal softens. Add egg and shortening. Beat well. Stir in nuts. Add flour mixture, stirring only until combined. Spread evenly in 6-cup ring mold coated with cooking spray.
Bake at 400° F about 25 minutes or unti wooden pick inserted near center comes out clean. Cool 10 minutes in pan. Remove from ring mold and cool completely on wire rack.
Frost with thin confectioners' icing and sprinkle with additional chopped nuts, if desired. Serve warm or cold.