01 - Preheat the oven to 425°F.
02 - Remove giblets from the chicken cavity and pat the chicken dry with paper towels.
03 - Rub olive oil and softened butter thoroughly over the chicken inside and out, then season with sea salt and freshly ground black pepper.
04 - Fill the chicken cavity with lemon halves, smashed garlic cloves, rosemary, thyme, and a portion of parsley.
05 - Optionally, tie the legs together using kitchen twine and tuck wing tips underneath the body for even cooking.
06 - Place carrots, onion, and celery evenly in a roasting pan, then set the chicken breast-side up on top.
07 - Roast in the preheated oven for approximately 1 hour and 15 minutes, until internal temperature reaches 165°F at the thickest part of the thigh and juices run clear.
08 - Allow the chicken to rest for 10 minutes before carving. Serve alongside the roasted vegetables and pan juices.