Preheat oven to 350ºF.
Carefully loosen skin from breast of chicken and insert truffle slices between skin and meat of chicken. Season chicken inside and out with salt and pepper generously and stuff cavity of chicken with onion, celery, carrot, thyme, sage, bay leaf and lemon. In a Dutch oven just large enough to hold the chicken and vegetables, place turned vegetables on bottom of pot and add chicken stock. Place chicken on top of vegetables and cover Dutch oven. Bake chicken for 1 1/4 hours, or until tender and cooked through. Serve with vegetables and pan drippings.
Yield: 4 servings