01 - Preheat your oven to 425°F for optimal roasting temperature.
02 - Combine minced garlic, lemon zest, lemon juice, olive oil, salt, pepper, thyme, and rosemary in a small bowl. Mix thoroughly to create a uniform marinade.
03 - Pat chicken completely dry with paper towels. Gently loosen skin over breast area and rub half the marinade directly onto meat beneath skin. Coat exterior thoroughly with remaining marinade.
04 - Fill chicken cavity with lemon rounds. Add additional fresh thyme or rosemary sprigs if desired for enhanced flavor.
05 - Place quartered onions, carrot chunks, and celery pieces in large roasting pan. Position chicken on vegetable bed, breast side facing up.
06 - Roast for 1 hour 15 minutes until thigh juices run clear and meat thermometer inserted into thickest thigh section reaches 165°F.
07 - Allow chicken to rest 10 to 15 minutes before carving. Serve accompanied by roasted vegetables and pan juices.