Stir together flour, soda, salt and cinnamon. Set aside.
In medium bowl, stir together banana, applesauce, milk and KELLOGG'S ALL-BRAN cereal. Let stand about 5 minutes or until cereal softens.
In large mixing bowl, beat margarine and sugar until combined Add egg. Beat well. Mix in cereal mixture. Stir in flour mixture, mixing until combined. Spread evenly in 9 x 5 x 3-inch loaf pan coated with cooking spray.
Bake at 350° F about 50 minutes or until wooden pick inserted near center comes out clean. Let cool 10 minutes in pan. Remove from pan and cool completely before slicing.