PRESS cookie dough onto bottom and 1 inch up sides of 13x9-inch baking pan. Bake at 350°F for 15 to 18 minutes or until lightly browned.
MICROWAVE caramels and water in medium microwavable bowl on HIGH 2 to 3 minutes or until smooth, stirring every minute. Pour caramel mixture over crust; top with chocolate chunks, peanuts and marshmallows.
BAKE 5 minutes or until marshmallows are lightly browned. Cool; cut into bars.
Great Substitute: Substitute refrigerated sliceable peanut butter cookies for sugar cookies.