1-Prepare the jelly broth one day ahead: Preheat oven to 400°F. Toss 2.5 to 3 lbs chicken backs and necks with 1 tablespoon vegetable oil, 2-inch sliced ginger, and 4 green onions chopped into 3-inch pieces. Roast in a covered pan until broth collects. Strain, refrigerate overnight until congealed. Scrape off fat, dice the jelly.

2-Make the wrappers: Mix 120 g all-purpose flour and pinch of salt. Gradually add 35 g hot water and 25 to 30 g cold water. Knead until smooth and elastic. Cover and let dough rest 30 minutes or more.

3-Prepare the filling: Mix 1 tablespoon grated ginger with a bit of hot water to release flavors. Combine with 8 oz fatty ground pork, 1 tablespoon light soy sauce, 4 teaspoons Shaoxing wine or dry sherry, 1/4 teaspoon salt, 1/4 teaspoon sugar, and 1/8 teaspoon white pepper. Beat well for springiness. Fold in diced chicken gelatin and 4 green onions finely minced. Refrigerate.

4-Form the dumplings: Roll rested dough into thin logs, cut into small pieces. Roll each into 3-inch wrappers, thicker in centers, thinner at edges. Add 1 tablespoon filling, pleat edges, seal with small opening on top.

5-Steam: Line bamboo steamer with napa cabbage or parchment. Steam over boiling water 8 to 10 minutes until wrappers turn translucent.

6-Serve: Enjoy hot with dipping sauce of Chinese black vinegar and very thinly sliced ginger.