PREHEAT oven to 350ºF. 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 into 9x5-inch loaf pan sprayed with cooking spray.
BAKE 55 min. to 1 hour 5 min. or until wooden toothpick inserted in centre comes out clean. Cool in pan 10 min.; remove to wire rack. Cool completely.
serving size = 1 slice (55 g)