Shanghai Soup Dumplings (Xiăolóngbāo 小籠包)

Bring 3 pounds chicken wings and 6 cups water to boil in large saucepan over medium-high heat, skimming off any scum that comes to surface. Reduce heat to low, partially cover, and simmer gently for 1 hour.

Add 1 (2‐inch) piece ginger, sliced into ¼-inch-thick rounds; 3 scallions, cut into 2-inch lengths; and ¼ ounce dried shiitake mushrooms, rinsed, and continue to simmer for 2 hours. Strain soup through fine-mesh strainer into large bowl or container; discard solids. Let soup settle for about 5 minutes, then, using wide, shallow spoon, skim excess fat from surface. Wipe pot clean with paper towels.

Return soup to now-empty pot. Bring to simmer over medium-high heat and cook until reduced to 2 cups, 10 to 15 minutes. Transfer soup to 13 by 9‐inch baking dish and let cool for 30 minutes. Cover and refrigerate until fully gelatinized, about 4 hours. Scrape any hardened fat from top of soup. (Jellied soup can be refrigerated for up to 5 days.) Using fork, mash jellied soup into ⅛‐inch pieces.

Place 2 cups (10 ounces) all-purpose flour in bowl of stand mixer and fit mixer with paddle. With mixer on medium-low speed, slowly add ¾ cup boiling water and 1 teaspoon vegetable oil until dough forms ball and clears sides of bowl, 2 to 4 minutes. If dough ball does not form, add extra boiling water 1 teaspoon at a time until dough ball forms. Transfer dough to counter and gently knead until mostly smooth, 2 to 3 minutes. Wrap dough in plastic wrap and let rest for at least 30 minutes or up to 4 hours.

Using clean, dry stand mixer fitted with paddle, beat 1 pound ground pork, 1 tablespoon Shaoxing wine, 1 tablespoon soy sauce, 1 minced scallion, 2 teaspoons toasted sesame oil, 1 teaspoon grated fresh ginger, 1 teaspoon sugar, ½ teaspoon table salt, and ⅛ teaspoon white pepper on medium speed until well combined, mixture has stiffened and started to pull away from sides of bowl, and pork has slightly lightened in color, about 2 minutes. Scrape down sides of bowl, add jellied soup, and mix on medium-low speed until incorporated, about 1 minute. Divide filling into 1-tablespoon portions (you should have at least 40 portions). Using wet hands, roll each portion into ball and arrange on parchment paper–lined rimmed baking sheet. Freeze until firm, about 15 minutes, then store in refrigerator until needed.

Roll dough into 12‐inch cylinder on counter, then cut cylinder into 4 equal pieces. Set 3 pieces aside and cover with plastic. Roll remaining piece into 8‐inch cylinder. Cut cylinder in half and cut each half into 7 equal pieces (each piece should weigh about ¼ ounce, or 8 grams). Roll each piece into ball. Place dough balls on lightly floured counter and lightly dust with flour. Using pie plate or palm of your hand, press each ball into 2‐inch disk. Cover disks with damp dish towel.

Working with 1 disk at a time, roll into 3‐inch round. Continue rolling outer 1-inch edge of dough to create 4‐inch round wrapper with tapered edges. As you roll, hold center of wrapper with nondominant hand and rotate dough slightly after each roll to maintain uniform shape. Re-cover wrapper with damp dish towel; do not overlap wrappers. Line additional 2 rimmed baking sheets with parchment paper and lightly dust with flour.

Place wrapper on fingers of nondominant hand and brush away any flour clinging to surface. Place 1 ball of filling in center of round. Steady dough by lightly pinching outer edge with thumb and index finger of nondominant hand. Using thumb and index finger of dominant hand, push edge of dough toward pinched portion to create first ¼-inch pleat on exterior of dumpling. Pinch pleat with fingers of nondominant hand to seal, and continue pinching to secure dough while creating next pleat. Continue with pleating and pinching motion, pinching each pleat to edge of previous pleat to create round purse-shape dumpling. Rotate dumpling as you pleat, and support dumpling base with palm of hand. As opening in top of dumpling narrows, you may need to gently push filling into dumpling and use very tips of fingers to create final pleats.

Pinch top of gathered dough edges together to seal dumpling. Gently twist off any excess dough from dumpling, leaving small point on top. Place dumpling pleated side up on prepared sheet and cover with plastic. Repeat with remaining dough and filling. (Dumplings can be refrigerated for up to 1 hour or frozen on sheet until solid, then transferred to zipper-lock bag and stored in freezer for up to 1 month. Do not thaw dumplings before cooking; increase steaming time to about 10 minutes.)

Bring 4 cups water to boil in 14‐inch flat-bottomed wok. Poke about 20 small holes in two 9-inch parchment rounds and lightly coat with vegetable oil spray. (Use leaves of napa cabbage in place of parchment if desired.) Place rounds in two 10-inch bamboo steamer baskets. Arrange 10 dumplings in each prepared basket so that they are not touching; stack baskets and cover. Reduce heat to maintain vigorous simmer and set steamer in wok. Steam until dumpling wrappers have translucent, glossy sheen, about 8 minutes. Serve immediately with Chinese black vinegar and fresh ginger matchsticks. (Before cooking second batch of dumplings, replenish water in wok and line steamer baskets with fresh parchment rounds.)