Place potatoes in a large saucepot; cover with water. Bring to a boil and cover. Cook for 20-25 minutes or until very tender; drain well - I used a colander
In a mixing bowl, mash potatoes. Add remainder of ingredients; beat until fluffy.
Transfer to a greased 2-qt., baking dish. Cover and refrigerate at this point if you're not going to bake right away.
Bring to room temperature if the potatoes have been refrigerated prior to baking
Bake at 350° for 40-45 minutes or until heated through. Sprinkle with additional cheese, if desired.
Notes
This is not a low-calorie dish and I only make it for special occasions.