Preheat oven to 375 degrees
Boil whole potatoes in salted water until just-done (they should be
soft but not mushy). Remove potatoes from water and allow them to cool.
While potatoes are cooling, melt butter and combine with mustard.
Cut each potato in half and scoop out a small depression in the center of each cut
side. Place potato halves skin side down on a parchment-paper-covered cookie
sheet. (Press down slightly if necessary to make the potatoes sit level).
Brush each potato liberally with the butter/mustard mixture, and place a cube of
cheese in the depression. Sprinkle the tops lightly with salt and pepper.
Bake until cheese is bubbly; about 15-20 minutes.
