Delicate xiaolongbao with thin wrappers bursting with savory pork soup are a Shanghai treasure. A high protein, fresh family dish with exquisite flavor.
Make aspic: Add pork skin to a pot of water, bring to a gentle simmer and cook for 1 hour, skimming foam. Strain, chill the liquid until set, then finely dice the aspic.
Prepare dough: Combine all-purpose flour and hot water in a bowl. Mix until shaggy, then knead for 10 minutes until smooth. Cover the dough and let rest for 30 minutes to relax gluten.
Make filling: In a large bowl, combine ground pork, soy sauce, Shaoxing wine, ginger, sugar, salt, white pepper, sesame oil, and scallions. Mix in the diced aspic until evenly distributed. Chill the mixture to keep filling firm.
Shape dumplings: Divide dough into 24 pieces. Roll each into a thin round wrapper (about 3 inches wide). Place a spoonful of filling in center of each, pleat the edges, and pinch to seal tightly to prevent soup from leaking.
Steam: Arrange xiaolongbao on parchment-lined steamer basket. Steam over medium-high heat for 8 minutes, ensuring the water is at a rolling boil but not touching the dumplings. Serve immediately while hot and soupy.