01 - Set your grill to medium-high heat, targeting approximately 400°F. Allow the grates to fully heat for even cooking.
02 - In a large mixing bowl, combine the cut potatoes with olive oil, chopped rosemary, thyme, parsley, minced garlic, kosher salt, and black pepper. Toss thoroughly until every piece is evenly coated.
03 - Tear two large sheets of heavy-duty aluminum foil. Divide the seasoned potato mixture evenly between the sheets, spreading each portion into a single even layer. Fold the foil over the potatoes and tightly crimp all edges to create sealed packets.
04 - Place the sealed foil packets directly onto the grill grates. Cook for 20 to 25 minutes, flipping once halfway through, until the potatoes are fork-tender and lightly browned on the edges.
05 - Carefully open the foil packets, watching for hot escaping steam. Sprinkle with grated Parmesan and additional fresh herbs if desired. Serve immediately while hot.