Sunday Dinner Mashed Potatoes

5 pounds potatoes, peeled and cubed
1 cup (8 ounces) sour cream
2 packages (3 ounces each) cream cheese, softened
3 tablespoons butter or margarine, divided
1 teaspoon salt
1 teaspoon onion salt
1/4 teaspoon pepper

Place potatoes in a Dutch oven; cover with water. Cover and bring to a boil. Cook for 20-25 minutes or until very tender; drain well.

In a large mixing bowl, mash potatoes. Add sour cream, cream cheese, 2 tablespoons butter, salt, onion salt and pepper; beat until fluffy. Transfer to a greased 2-qt. baking dish. Dot with the remaining butter. Bake, uncovered, at 350° for 20-25 minutes or until heated through. Makes 8 servings.