1/4 cup Chinese rice wine, or pale dry sherry
2 cups cold water
2 scallions, including green tops, cut into 3-inch lengths
PREPARE AHEAD
In a small bowl, cover the mushrooms with 1/2 cup of warm water and let them soak for 30 minutes. Remove them with a slotted spoon and discard the water. With a cleaver or sharp, cut away and discard the tough stems of the mushrooms and leave the caps whole.
Place the pork shoulder in a heavy pot or saucepan just large enough to hold it snugly. To blanch the pork, add enough cold water to cover it by 2 inches and, over high heat, bring the water to a boil. Let it boil briskly for 5 minutes, then transfer the meat from the pot to a colander and run hot tap water over it.
Discard the cooking water and replace the meat in the pot. Add the soy sauce, star anise, rock candy or sugar, wine, scallions and 2 cups of cold water. Bring to a boil and cover the pot. Reduce the heat to low and cook the meat for about 3 hours, adjusting the heat to keep the liquid at a simmer and turning the meat over 2 or 3 times during the cooking period. Then add the soaked mushrooms and cook 30 minutes longer. There should be about 1 cup of liquid left when the meat has finished cooking. If there is more, cook uncovered until the liquid is reduced.
Traditionally, the meat is served by transferring it to a deep platter and pouring the cooking juices over it. Decorate the cooked shoulder with the mushrooms. The rind and pork should be soft enough to be pulled off the bone with chopsticks or a fork. Less traditionally, the bone may be removed from the shoulder, and the meat (with the rind on) carved into thin slices and the sauce poured over it.
Will serve 6 to 8