01 - Preheat your oven to 400°F.
02 - Arrange the onion slices and carrot chunks in the bottom of a large roasting pan to form a flavorful base for the chicken.
03 - Rub the entire surface of the chicken with olive oil, then evenly distribute the kosher salt, black pepper, and lemon zest.
04 - Fill the chicken cavity with the halved lemons, garlic bulb halves, and fresh thyme sprigs.
05 - Use kitchen twine to tie the legs together securely. Tuck the wing tips underneath the body of the bird.
06 - Place the chicken breast-side up directly on top of the vegetable layer in the roasting pan.
07 - Roast in the preheated oven for 1 hour 10 minutes. Baste the chicken with pan juices once or twice during cooking. The chicken is done when juices run clear and an internal temperature of 165°F is reached at the thickest part of the thigh.
08 - Allow the roasted chicken to rest for 10 minutes before carving. This redistributes the juices throughout the meat. Serve with pan juices and roasted vegetables from the bottom of the pan.