01 - Preheat oven to 350°F.
02 - Remove giblets from turkey cavity and pat turkey completely dry with paper towels.
03 - In a bowl, combine softened butter, garlic, rosemary, thyme, parsley, and lemon zest until well blended.
04 - Gently loosen skin over breast and legs. Rub half the herb butter under the skin, spreading evenly. Rub remaining butter over the entire exterior surface.
05 - Season turkey cavity and exterior generously with salt and pepper.
06 - Place lemon, onion, celery, and carrot pieces inside the turkey cavity for added moisture and flavor.
07 - Tie legs together with kitchen twine and tuck wing tips under the body for even cooking.
08 - Set turkey breast-side up on a rack in a large roasting pan. Brush skin with olive oil.
09 - Roast for 2 to 2½ hours (approximately 13-15 minutes per pound). Baste every 45 minutes with pan juices. Tent breast loosely with foil if browning too quickly.
10 - Insert meat thermometer into thickest part of thigh, avoiding bone. Turkey is done when it reads 165°F.
11 - Transfer turkey to cutting board, cover loosely with foil, and let rest for 20-30 minutes before carving.
12 - Skim excess fat from roasting pan juices. Place pan over medium heat, add flour, and cook for 2 minutes while stirring constantly. Gradually whisk in broth and simmer until thickened. Season with salt and pepper to taste.