1. Pre-heat grill on high.2. Toss the potatoes with the onion, butter, olive oil, garlic, parsley, salt, and pepper.3. Spray a large piece of tin foil with cooking spray to avoid sticking.4. Add potato mixture to center of tin foil and seal all sides to create a packet.
5. Cook tin foil packet on pre-heated grill.6. Carefully open the packet and sprinkle in both types of cheese.7. Reseal foil packet and cook until cheese melts.8. Remove packet from grill and carefully open to serve!!