Make the pork stock and aspic: Rinse the Pork Bones and Pork Skin and blanch them in a pot of boiling Water for 3–5 minutes to remove impurities; discard the blanching liquid. Return the bones and skin to the pot, add fresh Water, sliced Ginger, halved Scallions, a splash of Shaoxing Wine and a pinch of Salt. Simmer gently, uncovered, for 3–4 hours until the liquid is deeply flavored and slightly gelatinous.
Strain the broth through a fine-mesh sieve into a bowl, discard solids, cool to room temperature and refrigerate until fully set into jelly (4–6 hours). If you already have ready-made Pork Aspic, you can skip the stock-making step and use that aspic instead.
Make the dough: combine All-Purpose Flour and a pinch of salt with warm water and knead until smooth and elastic (about 6–8 minutes). Cover and let rest at room temperature for at least 30 minutes to relax the gluten.
Prepare the filling: in a large bowl combine Ground Pork with Light Soy Sauce, a little Shaoxing Wine, grated Ginger, chopped Scallions, Sugar, Salt to taste, freshly ground White Pepper and a dash of Sesame Oil. Mix vigorously in one direction until the mixture becomes tacky and cohesive.
Cube the chilled pork aspic (either your homemade aspic from step 2 or the store-bought Pork Aspic) into small pieces and fold them gently into the seasoned pork mixture; add a tablespoon or two of cold Water if the filling needs loosening. The aspic will melt during steaming and create the signature soup inside each dumpling.
Portion and roll wrappers: roll the rested dough into a long cylinder and cut it into equal pieces (about 18–24 portions). Flatten each piece and roll into thin rounds, thinner at the edges and slightly thicker in the center so they hold the filling without tearing.
Assemble the xiaolongbao: place a generous teaspoon (about 1 tbsp) of filling in the center of each wrapper, then pleat and pinch the top to seal, making several tight pleats to keep the soup enclosed. Work with slightly floured hands and keep unused wrappers covered to prevent drying.
Prepare the steamer: line the steaming basket with Napa Cabbage Leaves or parchment paper to prevent sticking. Arrange the dumplings leaving space between them.
Steam the dumplings over boiling water for 8–10 minutes (steam time depends on size), until the wrappers are translucent and the filling is cooked through and hot — the aspic should be fully melted into a rich broth inside each dumpling.
Make the dipping sauce by combining Chinkiang Vinegar with thinly julienned Ginger (and a little light soy sauce or chili oil if you like).
Serve immediately: transfer dumplings carefully to plates or a shallow bowl, dip into the vinegar-ginger sauce, and enjoy each bun by biting a small hole to sip the hot soup before eating the rest.
