Xiaolongbao is a type of Chinese dim sum, or "small dish", originating in Shanghai. It is often called a soup dumpling because the filling contains aspic, a savory gelatin which melts into broth during the cooking process. The Chinese name is pronounced "sow-long-bough" and can be translated as "little basket dumpling" or "small steamed bun." Both are fitting, as xiaolongbao are steamed and then served in the steamer basket in sets of four, six or eight. The best xiaolongbao have thin, almost translucent wrappers surrounding a filling of meat, usually minced pork, in an intensely flavored broth.
Wrappers for xiaolongbao are made from a hot water dough, a simple mixture of all-purpose flour and hot water, with just enough cold water added to make the dough cool enough to handle. The dough is briefly kneaded and then allowed to rest long enough for the gluten to relax. This makes it easier to roll the dough into very thin sheets for the wrappers. Small portions of dough are rolled out into circles as thinly as possible.
Assembling xiaolongbao requires patience and some skill. A spoonful of filling is placed in the center of each circle. The edges of the circle are brought upwards into a cup shape, then pleated to mold the dough around the filling. Precise pleating is considered the sign of a good xiaolongbao. When the pleating is complete, the very top of the wrapper is twisted to hold it in place.
The most common filling is seasoned, minced pork, but other meat or seafood varieties can be used as well. Meat is minced or ground, and mixed with cubes of aspic. Aspic is meat or seafood stock which has enough gelatin in it to become solid when chilled. The gelatin can be added as an unflavored commercial powder, but the most intensely flavored aspic comes from stock made with enough meat to have large quantities of naturally occurring gelatin.
After cooking, the broth is strained and allowed to cool and congeal, then the aspic is cut into small cubes and mixed with the minced pork or other meat. The assembled dumplings are placed in a steamer basket lined with the large outer leaves of napa cabbage, or other suitable leaves, and steamed for 7 to 10 minutes. Xiaolongbao is served hot, usually still in the steamer basket, with a dipping sauce of vinegar and diced ginger.