01 - Set oven temperature to 425°F.
02 - Pat the chicken dry with paper towels and rub the outside and cavity with olive oil or melted butter, salt, and black pepper.
03 - Fill the chicken cavity with lemon halves, smashed garlic cloves, 2 sprigs thyme, and 1 sprig rosemary.
04 - Tie the legs together with kitchen twine and tuck the wings underneath the body.
05 - Place carrots, onions, and celery into a large roasting pan. Scatter remaining thyme and rosemary over the vegetables and position the chicken breast side up on top.
06 - Roast for 1 hour and 20 minutes, or until juices run clear and an instant-read thermometer inserted into the thickest thigh registers 165°F.
07 - Let the chicken rest for 10 to 15 minutes before carving. Garnish with chopped parsley if desired and serve alongside the roasted vegetables.