1.Take a heavy duty foil and cut four pieces of it measuring 18 by 12 inches.
2.Cut potatoes crosswise in slices of 1/4 inch thickness.
3.In every rectangle, put potato retaining the original shape.
4.Keep a slice of onion between the potato cuts.
5.Apply 2 tablespoons butter on the top and add a sprinkling of 1/2 tea spoon salt and some paprika.
6.Fold the foil twice to close.
7.Repeat the process with the other three foil pieces.
8.Put the packages on coal and grill for 20 minutes.