01 - Set the oven to 400°F to ensure it reaches the proper roasting temperature.
02 - Pat the chicken dry with paper towels and gently loosen the skin over the breast with your fingers without tearing.
03 - Combine olive oil, softened butter, sea salt, and black pepper. Rub half of this mixture beneath the skin and spread the remaining over the skin surface.
04 - Fill the chicken cavity with the halved garlic head, lemon halves, and half of the thyme and rosemary sprigs.
05 - Tie the legs together with kitchen twine and tuck the wings under the body to maintain shape during roasting.
06 - Place carrots, onions, and celery in a roasting pan. Scatter the remaining herbs on top and position the chicken breast-side up over the vegetables.
07 - Cook for 1 hour and 15 minutes or until the internal temperature at the thickest part of the thigh reaches 165°F and juices run clear.
08 - Let the chicken rest loosely covered with foil for 10 minutes to allow juices to redistribute before carving.
09 - Carve the chicken and serve alongside the roasted vegetables and pan juices.