Lightly butter a large casserole (I used an 8" x 12") or two smaller ones that are about 8"x 8".
Peel and cut the potatoes into quarters.
Place in a large saucepan and cover with water.
Bring to a boil and then turn down to medium-high, crack the lid, but keep it at a low boil.
Cook about 15 minutes or until you can easily pierce the potatoes with a fork.
Drain and put the potatoes back into the pan.
Mash with a potato masher.
Add the remaining ingredients and mix well.
Put into the prepared casserole or casseroles.
You can freeze or refrigerate at this time.
Bake at 350° for 30 minutes.