Preheat oven to 350 degrees F. Place 2 large sheets of Reynolds Wrap® Aluminum Foil onto a clean surface.
Divide ingredients. In the center of each piece of foil, place an even, single layer of onion and lemon slices. Top the onion and lemon with lobster tails, cut-side up (2 per foil sheet), and corn. In a small mixing bowl, whisk together butter, wine, garlic and tarragon.
Gently fold up the edges of the foil around the food to create a shallow bowl. Pour butter mixture over the tails and corn and top with thyme sprigs. Season with salt and pepper. Double fold top and ends to seal packet, leaving room for heat circulation inside.
Bake for 20-25 minutes or until tails just cook through. Open packets carefully by cutting along top fold with a sharp knife, allowing steam to escape; then open top of foil packet. Serve with drawn butter and lemon wedges.