Make-Ahead Mashed Potatoes

Directions

1. 1
   Peel and quarter potatoes.
2. 2
   In a 1 1/2-quart microwave-safe casserole, combine potatoes and 1/2 cup water.
3. 3
   Cook, covered, in the microwave on High for 15 to 20 minutes or until very tender. Drain and mash potatoes with mixer.
4. 4
   Add sour cream, cream cheese, 1 tablespoon margarine, onion and salt and pepper.
5. 5
   Gradually beat in enough milk to make smooth and fluffy.
6. 6
   Turn into a greased 1 1/2-quart casserole.
7. 7
   Cover and chill up to 24 hours.