01 - Preheat oven to 400°F. Arrange onion slices and carrot chunks in the bottom of a large roasting pan to create a flavorful bed for the chicken.
02 - Rub the entire chicken surface with olive oil, then evenly distribute kosher salt, black pepper, and fresh lemon zest over the skin.
03 - Fill the chicken cavity with both halved lemons, the halved garlic bulb, and fresh thyme sprigs to infuse aromatic flavors during roasting.
04 - Secure the legs together with kitchen twine and tuck the wing tips under the body to ensure even cooking and maintain an attractive shape.
05 - Place the chicken breast-side up directly on top of the vegetable bed in the roasting pan.
06 - Roast in the preheated oven for 1 hour 10 minutes, basting once or twice with pan juices, until the internal temperature reaches 165°F and juices run clear when pierced.
07 - Allow the chicken to rest for 10 minutes before carving. This redistributes the juices for more tender meat. Serve with pan juices and roasted vegetables.