For each serving, peel a medium size potato, and slice thinly. Lay slices in overlapping layers on a square of aluminum foil. Dot with 1 tablespoons butter and sprinkle a little salt and pepper. Make a pouch or cup and add 2 tablespoons milk. Seal tightly with a double fold. Place on grill near coals and cook about 15 minutes. Open top to see if they are done, If not reseal and cook longer. At this point you may sprinkle some cheese on the potatoes and grill till melted.