In a small bowl, mix the stock with the sherry, soy sauce, brown sugar, star anise, garlic and five-spice powder.
To make star anise pork shoulder: Season the pork with salt and pepper. Heat the oil in a large enameled cast-iron casserole. Add the pork and cook over moderate heat, turning occasionally, until browned all over, about 15 minutes. Add the sauce mixture and bring to a boil, scraping up any browned bits from the bottom of the casserole. Cover tightly and cook over low heat for about 3 hours, turning the roast every 30 minutes, until very tender. Remove the pork and boil the sauce until it is reduced to 1 cup, about 5 minutes. Discard the strings. Pull the pork into long shreds and return to the casserole. Garnish with the cilantro and serve.
To make star anise pork chops: Pour the sauce mixture into a large resealable plastic bag. Add the chops and marinate in the refrigerator for at least 2 hours or for up to 8 hours. Drain the chops, pat dry and season with salt and pepper. Heat the oil in a large skillet. Add the pork chops and cook over moderately high heat, turning occasionally, until browned and cooked through, about 12 minutes. Serve the pork chops.