Wash, dry, and oil the skins of the potatoes.
Bake the potatoes about 1 hour at 400 C or until tender.
Cool until easy to handle.
Slice the cooked potatoes in half lengthwise.
Scoop out the soft potatoes and mix with the butter, milk, salt, spices if desired, and egg yolks.
Beat one minute.
Fold the stiffly beaten egg whites into the mixture.
Refill the potato shells.
Place these filled shells in an oiled dish.
Bake 10 minutes at 450 Degree or until hot through.