In a large bowl, toss together the halved potatoes, olive oil, butter, garlic salt and freshly cracked black pepper.
Tear 4 large sheets of Reynolds Wrap(R) Aluminum Foil, each about 16 inches long. Divide the potato mixture evenly between the sheets of foil. Bring up foil sides. Double fold top and ends to seal packet, leaving room for heat circulation inside. Place the packets on a baking sheet and transfer to the oven. Cook for 25 minutes.
Remove one packet from the oven. Open packet carefully by cutting along top fold with a sharp knife, allowing steam to escape; then open top of foil packet. Check to see if the potatoes are fully cooked and fork tender; if not, return to the oven for 5 more minutes.
Once cooked, open up the packets and top each portion of potatoes with cheese and herbs. Let the cheese melt before serving. Season with salt and pepper to taste.