- With the rack in the middle position, preheat the oven to 400°F (200°C).
- Place the chicken on a large plate. Season the inside and outside with the coarse salt and rub with the cut side of 1 lemon half for about 3 minutes or until the salt begins to dissolve. Let rest for 15 minutes. Discard the lemon half.
- Stuff the inside of the chicken with the remaining lemon halves and the celery. Brush the chicken with half of the oil (1 tbsp/15 ml). Season with pepper.
- In a large Dutch oven, combine the carrots and celeriac with the remaining oil (1 tbsp/15 ml). Season with salt and pepper. Place the chicken in the Dutch oven. Bake uncovered for 1 hour and 45 minutes or until a meat thermometer inserted into the thigh, without touching the bone, reads 180°F (82°C).
- Remove from the oven. Sprinkle the parsley, green onion and Parmesan over the chicken and vegetables.
- Serve the chicken and vegetables drizzled with the lemon and cooking juices.