Spoon any leftover fat and juices from the roasted chicken tray into a flameproof casserole dish and melt over a medium heat. Tip in the onions, carrots, parsnip, celery and garlic, and fry, partially covered, over a low heat for 8-10 mins until softened. Mix in the plain flour, bay leaves and half the thyme, cook for a couple of minutes, then add the stock and shredded chicken. Bring back to a gentle simmer and cook for 15-20 mins until everything is tender. Season.
