Potato, as many as needed, sliced thin
Onions, as many as needed, sliced thin
Butter, to taste
Salt and pepper, to taste

Place 1 layer of potatoes and 1 layer of onions (torn apart) several pads of butter and salt and pepper on two layers of foil. Repeat until all is used. Seal, bake in oven. If you have a lot of potato make two packages.