Lemon-Thyme Split-Roasted Turkey

Position the oven rack in the bottom third of the oven. Preheat oven to 375°F. In a large roasting pan combine onions, lemons, celery, thyme sprigs, and garlic; set aside.

In a medium bowl combine butter, snipped thyme, lemon peel, lemon juice, shallot, oil, salt, and pepper; set aside.

Remove neck and giblets from turkey; discard. Rinse turkey; pat dry with paper towels. Place turkey, breast side down, on a cutting board. Using kitchen shears, make a lengthwise cut down one side of the backbone, starting from the neck end. Repeat on the other side of the backbone. Remove and discard backbone. Turn turkey, cut side down. Flatten turkey as much as possible with your hands. Cut off and discard tips of wings. Using kitchen shears or a large sharp knife, carefully cut through the entire breastbone, creating two equal halves.

Rub herb-butter mixture over turkey on all sides, massaging some of the mixture underneath the skin. Place turkey halves, skin sides up, on top of vegetables in roasting pan. Insert an oven-going meat thermometer into the center of an inside thigh muscle. The thermometer should not touch bone.

Roast, uncovered, for 1-1/2 to 2 hours or until the thermometer registers 175°F. (The juices should run clear and drumsticks should move easily in their sockets.) Remove from oven. Cover turkey halves with foil; let stand for 15 minutes before carving. Discard vegetables in roasting pan.