Clean potatoes well. Bake in oven at 350 directly on oven rack until very tender, about 1 hour. Remove potatoes from oven and allow to cool. This is best done in advance. Preheat oven to 400 Degrees F. Cut potatoes in half and scoop out potato, making sure not to tear shell. Set shells aside. Put potato inside into mixing bowl, add butter and seasoning and beat. Add milk a little at a time and beat to a smooth, light consistency. If it's too thick, add more of the milk. Add cheese and mix quickly just until well blended. Scoop a generous amount into each potato shell and bake at 400 degrees F until lightly browned. About 20-30 minutes. Devour! Note: I like to mix sharp and medium cheddar to give the best flavor. I frequently also add some grated parmesan.