01 - Preheat grill to medium-high heat, approximately 400°F.
02 - In a large bowl, combine cut potatoes, olive oil, rosemary, thyme, parsley, garlic, salt, and pepper. Toss thoroughly until potatoes are evenly coated.
03 - Cut two large sheets of heavy-duty aluminum foil. Divide potato mixture between sheets, spreading into an even layer. Fold foil over potatoes and crimp edges tightly to seal, creating two secure packets.
04 - Place foil packets on grill grates. Grill for 20 to 25 minutes, turning once halfway through cooking time, until potatoes are tender and lightly browned.
05 - Carefully open foil packets, watching for escaping hot steam. Sprinkle with Parmesan and extra fresh herbs if desired. Serve immediately while hot.