Prepare grill to medium heat. Place 2 (28x18-inch) sheets of aluminum foil on top of each other.
Layer half the potatoes in the center of the foil. Sprinkle with half of the remaining ingredients; salt and pepper to taste. Repeat layers. Crimp and seal each sheet of foil individually, creating one packet.
Place foil packet on grill. Grill 20-25 minutes, turning packet over and around occasionally. Remove from grill and carefully open packet.