In a skillet, saute onion and celery in the 1/4 cup margarine until the onion i s translucent. Remove from heat. Add flour, salt, and pepper; stir. Place in Crock-Pot. Add water. Tehn stir in potatoes, canned mushrooms, and carrots. Cover and cook on Low 6 to 8 hours or on High for 3 to 4 hours. If on Low tur n to High. Add milk and Parmesan cheese and cook 30 minutes. Serve.
Shortcut: Use 2 cups frozen hash browns and 1 cup frozen carrots and cook on High for 2 t o 3 hours.