This recipe can be made ahead and refrigerated for several hours before grilling.
1/2 cup lemon juice
1/4 cup water
1/4 cup olive oil
2 cloves garlic, minced
1-1/2 tsp dried oregano, preferably Greek
1 tsp salt
1/4 tsp pepper
2 lb. potatoes, peeled (about 5 medium)
1 onion, thinly sliced
Step 1: In a large bowl, whisk together lemon juice, water, 3 tbsp of the oil, garlic, oregano, salt and pepper.
Step 2: Slice potatoes lengthwise into thick wedges. Add to bowl and toss with lemon mixture.
Step 3: Tear off two 18" square pieces of heavy-duty foil. Place one piece on a baking sheet, folding up edges slightly on all sides. Brush centre area with remaining oil.
Step 4: Spread onions over foil. Spread the potato mixture, including the liquid, out in one layer over onions.
Step 5: Cover potatoes with second sheet of foil, double folding and crimping to tightly seal. (Packet can be refrigerated for several hours before grilling.)
Step 6: Slide packet onto grill. Close barbecue lid. Cook over medium heat (the internal barbecue temperature should not exceed 350°F) for 30 to 40 minutes or until potatoes are very tender and most of liquid has been absorbed.
Step 7: Let stand several minutes before transferring to serving dish.