HEAT grill to medium heat.
MICROWAVE potatoes, carrots and water in microwaveable bowl covered with waxed paper on HIGH 5 to 7 min. or just until potatoes are crisp-tender; drain well. Mix 1/3 cup cheese and dressing. Add to potato mixture; mix lightly.
SPOON onto center of large sheet of heavy-duty foil sprayed with cooking spray; fold to make packet. Place on upper shelf of grill.
GRILL 15 to 20 min. or until vegetables are tender. Cut slits in foil to release steam before carefully opening packet. Sprinkle potato mixture with parsley and remaining cheese.