Prepare Filling A or B by combining the ingredients. Place approximately 1 tablespoon filling on the center of each wrapper. Holding the wrapper on your left fingers, encircle it from below with your right thumb and index finger, gathering the wrapper up around the filling. Squeeze gently around the middle to make a kind of neck; some of the filling should emerge at the top. The bundle should hold together securely or it will collapse during steaming. Pat the bottom with your left hand to make a flat base. If the skin is not too floppy, you can also turn the edge slightly outward (like an open flower), pinching it if necessary to make it secure. Place a layer of damp cloth in a bamboo steaming basket or on a flat, perforated race (you can use a heatproof plate if you have neither of these, but circulation of steam is somewhat impaired this way). Arrange the shao mai on it. With the rack well above the boiling water in a steamer, steam for 10 minutes (if frozen, do not defrost first). They will stick to the cloth, but if you wash and reuse the same cloth each time, they will not stick as much. Serve while still hot, before the skin hardens -as is, or with small dipping saucers of soy sauce and mushroom liquid (from the black mushrooms), mixed in equal proportions. Add a few drops of sesame oil. Advance preparation: These can be assembled in advance, frozen, and steamed just prior to serving. *