Place cauliflower and broccoli in 2-qt. microwaveable dish. Add water; cover. Microwave on HIGH 8 to 10 minute or until vegetables are tender; drain. Set aside.
Microwave cream cheese and milk in 2-cup microwaveable measuring cup or medium bowl 1 minute or until cream cheese is melted and mixture is well blended when stirred. Add sour cream; mix well. Pour over vegetables; sprinkle with Cheddar cheese.
Microwave 2 minute or until cheese is melted.
Mix cracker crumbs and Parmesan cheese. Sprinkle over vegetables.