I've always loved these! They were definitely a favorite when I was a kid. I just can't seem to get them exactly the same way my mom used to.....but I continue to try!
Usually 1 or 1/2 potatoes per person (you can make your own decision as to how large you want your portions to be)
Slice your potatoes fairly thin (I like to use russet or Yukon gold) and pile them up on a large square of aluminum foil. Gather the sides up around the potatoes, making a bowl. Add 2-3 pats of butter and a sprinkle of Parmesan cheese and close them up. Grill them on a rack, not directly on the grill or directly over the coals - the bottoms will burn that way. Grill them over med-high heat for 30-45 mins. Cooking time will vary depending on your grill heat. You can open the top of the foil to check the potatoes...when a fork is inserted easily and the edges are beginning to brown, they are done.