Prepare the Potatoes – Wash, scrub, and dry the potatoes, then cut them in half for mini-sized. Alternatively, for baby-sized or larger potatoes, cut into quarters or ½-inch thick slices to form discs.
Season the Potatoes – Add the potatoes to a medium bowl. Drizzle on the olive oil, then sprinkle on the salt, garlic powder, Italian seasoning (if using), and black pepper. Toss to evenly coat.
Wrap in Foil – Tear two 20" long sheets of heavy-duty foil and overlap them by 8" on a large sheet pan to form a wide base. Press it into the pan to create a border, then brush with olive oil or spray with cooking spray. Spread the potatoes in a single layer, cut side down. Top with two more overlapping foil sheets and crimp the edges to seal, leaving some space inside for steam to circulate.
Grill the Potatoes – Heat the grill to medium-high heat, between 375 to 400°F (190 to 204°C). Do not overheat or the potatoes will brown too quickly! Place the foil packet on the grill and close the lid. Cook until the cut side is golden brown, about 15 to 20 minutes. Open the lid and carefully remove the top layer of foil, letting the steam escape away from you—then discard the foil. Use tongs to flip the potatoes. Cover and cook for an additional 5 minutes, or until fork-tender. Transfer the potatoes on the foil back to the sheet pan using tongs.
To Serve – Transfer the potatoes to a serving platter. Garnish with parmesan cheese and parsley if desired.
Notes
Using Regular Foil: If using regular foil instead of heavy-duty, use two layers (eight total to make the foil packet).
To Avoid Direct Foil Contact: Place the seasoned potatoes in a single layer between two pieces of parchment paper (rated to 420ºF and above), then seal the packet in foil before grilling.
Storing: Refrigerate in an airtight container for up to 5 days.
Reheating: Microwave on high in 30-second intervals until hot. For a crispy texture, saute in olive oil over medium-low heat until warmed through and crisp. Alternatively, reheat on a foil-lined sheet pan at 400°F (204ºC) until hot.