1. Sift together flour, baking powder, soda, salt, and sugar. Set aside.
2. Break egg into mixing bowl; beat well. Stir in vanilla, butter, lemon juice, and bananas. Add flour mixture; beat until well-combined. Mix in KELLOGG'S RAISIN BRAN cereal and walnuts. Pour into greased and waxed paper-lined 9 x 5 x 3-inch loaf pan.
3. Bake at 350° F about 1 hour or until wooden pick inserted near center comes out clean. Remove from oven; cool in pan about 5 minutes then remove from pan to cooling rack.