1. Carefully rinse and pat dry a 19 lb turkey (thawed if frozen). Remove neck and giblets and save for another use.
2. Heat oven to 375 degrees .
3. Heat oven to 375 degrees . Cut an onion into quarters and place in cavity along with 2 cloves smashed garlic and 1 lemon, cut into quarters. Season turkey with 1 tsp salt and 1/2 tsp pepper (add your favorite herbs, if desired).
4. Tuck legs under natural flap of skin or tie together. Fold wings under. Place turkey on a rack in a large roasting pan.
5. Roast at 375 degrees for 35 minutes. Reduce oven temperature to 325 degrees and continue to roast turkey (cover with foil if its browning too quickly) for 1 hour, 50 minutes, or until a thermometer registers 165 degrees in thickest part of thigh (without touching bone).
6. Remove turkey to a platter, garnish with herbs and orange and lemon slices, and let rest for 20 to 30 minutes before carving.