While I've never done it I have read many recipes for doing it. All of the recipes use a combination of cream cheese and sour cream. Here's an example of one (which comes from a freezer meal cookbook):
*Exported from MasterCook *
Make Ahead Garlic Mashed Potatoes
Recipe By : Adapted from 30 Day Gourmet Freezer Manual
Serving Size : 8 Preparation Time :0:00
Amount Measure Ingredient -- Preparation Method
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5 pounds potatoes -- peel and quarter
1 teaspoon garlic powder
3 tablespoons butter or margarine -- melted
1 teaspoon salt
8 ounces cream cheese -- softened
Place peeled and quartered potatoes in a sauce pan and cover completely with water. Bring to a boil then boil gently until potatoes are tender. Drain potatoes well.
In a large bowl, combine potatoes, cream cheese, egg, garlic powder and salt. Mash well with an electric mixer or by hand if you don't have one. Spoon potatoes into a (Pam) spray treated or greased 3 quart casserole or a 9 x 13 pan.
Drizzle or brush melted butter over potatoes. Refrigerate for up to 2 days or label and freeze for later. Freeze in a Ziploc Bag.
To serve: thaw completely. Bake at 375 degrees for 30 to 40 minutes until the top is golden.
Options: 1/4 cup crumbled crisp bacon may be stirred in for great flavor. Potatoes may also be topped with 1/2 cup shredded cheddar cheese.
Adapted from "30 Day Gourmet Freezer Cooking Manual"
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Per serving: 397 Calories (kcal); 17g Total Fat; (38% calories from fat); 10g Protein; 53g Carbohydrate; 66mg Cholesterol; 419mg Sodium
Food Exchanges: 3 1/2 Grain(Starch); 1/2 Lean Meat; 0 Vegetable; 0 Fruit; 3 Fat; 0 Other Carbohydrates
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