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.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.