MIX flour, sugar, baking powder, baking soda and salt in large bowl. Beat egg in medium bowl; stir in bananas, cereal, water, oil and vanilla. Add to flour mixture; stir just until moistened. (Batter will be lumpy.)
POUR batter into 9x5-inch loaf pan sprayed with cooking spray.
BAKE at 350°F for 55 to 1 hour 5 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pan. Cool completely on wire rack.