In a small bowl, combine oats and boiling water; let stand for 5 minutes. In a large bowl, beat the egg whites, bananas, sugars, oil and vanilla until blended. Combine the dry ingredients; gradually add to creamed mixture. Stir in the oat mixture.
Spread into a 13x9-in. pan coated with cooking spray. Bake at 350° for 20-25 minutes or until a toothpick inserted in the center comes out clean (do not overbake). Cool on a wire rack. Cut into bars.