Ingredients
1 (4-to-5-pound) fresh or frozen (thawed) Long Island duck
7 scallions, trimmed
2 (1/2-inch thick) slices fresh ginger
1/4 cup honey
2 tablespoons cornstarch
3 tablespoons Shao Hsing (Chinese cooking wine) or dry sherry
1 tablespoon white vinegar
12 to 15 frozen steamed rolls
Sweet black bean sauce or hoisin sauce, for serving
Preparation
In a very cool room, tie duck wings together using kitchen twine. In a cool room, hang duck from kitchen twine over a large bowl overnight, about 8 hours.
Fill a large pot with 4 cups water, 2 scallions, ginger, and honey; cover and bring to a boil. In a medium bowl, whisk together cornstarch and 1 cup cold water until well combined. Whisk cornstarch mixture into boiling water mixture until it is the consistency of a light gravy. Stir in wine and vinegar; remove sauce from heat.
Add duck to pot and spoon over sauce, for 3 to 5 minutes, until very well coated. Remove from sauce and hang duck again, in a cool room, over a large bowl for 4 hours.
Preheat oven to 300 degrees.
Fill the drip tray of a vertical poultry roaster with water; set in a roasting pan. Place duck on vertical roaster and transfer to oven. Roast until duck is golden and an instant-read thermometer inserted into the thickest part of the thigh (but not touching the bone) reaches 175 degrees. Take care with duck grease as you roast; if too much begins to accumulate in roasting pan, ladle into a disposable heatproof container as the duck cooks and discard.
Meanwhile, prepare frozen steamed rolls according to package directions. Quarter white parts of remaining 5 scallions and cut into 2-inch pieces, reserving green parts for another use.
Thinly slice duck and serve with steamed rolls, scallions, and sweet bean or hoisin sauce.
