Stuff the fattened pullet with mushrooms sautéed in Beurre Noisette then roast it in the oven until nicely coloured but only half cooked.
Place the half-cooked pullet in an earthenware Terrine, surround with the garnish, cover with the lid and seal with flour and water paste. Place in the oven to finish cooking for 45 minutes.
Serve the chicken in the dish as it is. If required it may be accompanied with a sauceboat of good chicken gravy.