Mashed Potato Casserole
["4 1/2 to 5 lb. Russet potatoes (about 8 large potatoes)", "1 (8 oz.) pkg. cream cheese (at room temperature)", "1 c. sour cream", "2 tsp. garlic salt or to taste", "1/2 tsp. pepper or to taste", "1/4 c. butter or margarine"]
["Peel potatoes.", "In a 5-quart pan, bring about 2-inches water to a boil; add potatoes.", "Cover and boil until tender throughout when pierced (about 40 minutes).", "Drain, then mash well.", "In small bowl of electric mixer, beat cream cheese and sour cream until smooth; gradually add to potatoes, beating until smoothly blended.", "Beat in garlic salt and pepper.", "Turn mixture into a buttered shallow 3 or 4-quart casserole.", "Dot with butter or margarine.", "Cover with lid or foil.", "At this point, you may refrigerate for up to 3 days; bring to room temperature before baking.", "Bake, covered, in a 350\u00b0 oven until heated through (50 to 60 minutes).", "Yields 12 to 15 servings."]
["Russet potatoes", "cream cheese", "sour cream", "garlic salt", "pepper", "butter"]