Chicken Roasted on a Clay Cone with Vanilla Mustard Sauce

Cooking a small chicken on a slowly revolving spit will, if basted regularly, produce an evenly roasted bird with moist, velvety flesh and wonderfully crisp skin. But there are a number of other ways to obtain the same result, especially with clay. One way is to roast the chicken in an upright position so it will self-baste as the fat flows downward. There are a number of excellent devices for doing this, including various metal cones, though I think these carry heat too quickly to the cavi