Combine vegetables in 2-qt. microwaveable casserole.
Add water; cover with lid. Microwave on HIGH 8 to 10 min. or until vegetables are tender; drain.
Microwave cream cheese and milk in 2-cup microwaveable measuring cup or medium bowl 1 min. or until cream cheese is melted and mixture is well blended when stirred. Stir in sour cream; pour over vegetables.
Sprinkle with cheddar; microwave 2 min. or until melted.
Mix cracker crumbs and Parmesan; sprinkle over vegetables.