Xiaolongbao

Xiaolongbao are delicate steamed dumplings that hold a mouthful of hot broth inside a thin, pleated wrapper. They are Shanghai's most technically demanding dim sum classic, built around a trick most diners never think about until the first bite scalds them.

What it really is

The filling starts as minced pork mixed with an aspic — broth set with gelatine until it's solid enough to fold into the dumpling like any other filling. Wrapped in a thin dough and pleated shut at the top into a small, twisted knot, the dumpling steams until the aspic melts back into liquid broth, trapped inside a wrapper that has to be thin enough to see through yet strong enough not to split under the weight of the soup it's holding.

The broth is folded in solid, not poured in liquid. There's no other way to seal a soup inside a paper-thin wrapper — the aspic trick is the entire reason xiaolongbao can hold liquid at all, and it's what separates them from a plain steamed dumpling.

How it is served

• In the bamboo steamer basket they cooked in, straight to the table.
• With a small dish of vinegar and shredded ginger for dipping.
• Eaten with a spoon underneath, since biting straight in sends hot broth everywhere.

How to write it on the menu

• Flag the wheat in the wrapper and the soy in the filling and dip.
• Warn guests to bite carefully or use the spoon-and-straw method, since the scalding broth is the most common surprise on a first order.
• Say how many come per portion, since these are always sold and eaten in a set of several small dumplings.