Peel potatoes, and cut into 1-inch cubes. Cook in a medium saucepan in boiling water to cover 15 to 20 minutes or until tender; drain and place into a large mixing bowl.
Add cream cheese and next 4 ingredients; beat at medium speed with an electric mixer until smooth and fluffy (do not overbeat). Spoon into a lightly greased 13- x 9-inch or 3-quart baking dish.
Bake, covered, at 325° for 50 minutes or until thoroughly heated; garnish, if desired.
Note: Unbaked mashed potatoes may be chilled up to 2 days. Let stand at room temperature 30 minutes, and bake as directed.