HEAT oven to 350°F.
MIX brownie mix, applesauce, 2 egg whites and water until blended. Pour into 13x9-inch pan sprayed with cooking spray.
BEAT Neufchatel, sugar, flour and remaining egg white with mixer until blended; spoon over brownie batter. Swirl gently with knife.
BAKE 28 to 30 min. or until toothpick inserted in center comes out with fudgy crumbs. (Do not overbake.) Cool completely.