Make-Ahead Mashed Potatoes

This recipe is from, "The Essential Mormon Cookbook." I made them last night and they are really good!

5 pounds potatoes, cooked and mashed
1 (8 ounce) package cream cheese
1 cup sour cream
1/2 cup milk
2 teaspoons garlic salt
pepper to taste

Combine mashed potatoes, cream cheese, sour cream, milk, garlic salt and pepper. Mix well and place in a large, greased casserole dish. If making ahead, refrigerate. otherwise, cover and bake at 325 degrees F. for 45 minutes. (If refrigerated first, let stand 30 mins at room temperature and then bake as directed.) Makes 6-8 servings.