What Are Soup Dumplings?.

Xiao long bao — soup dumplings — are thin-skinned steamed dumplings holding both a pork filling and a mouthful of hot broth. The broth is not injected or poured in. Stock rich enough in collagen to set solid when cold is cubed, folded into the filling, and melts back into liquid as the dumpling steams.

That is the entire trick, and it is a good one: the dumpling is sealed cold and served hot, so the soup appears somewhere between the kitchen and your table.

How they are made

1. Aspic. Pork skin, bones and sometimes chicken are simmered for hours until the stock is thick with gelatine, then chilled until it sets firm. It is cut into small cubes.
2. The filling. Ground pork — traditionally with a good amount of fat — is seasoned with ginger, soy, rice wine and white pepper, then mixed with the aspic cubes.
3. The wrapper. A hot-water or partly hot-water dough, rolled very thin at the edges and slightly thicker at the base so it can hold liquid without bursting.
4. The pleat. Eighteen folds is the number the famous Shanghai restaurants quote, twisted closed at the top. More pleats mean a thinner, more even wrapper; a dumpling with six thick folds is a different, sturdier animal.
5. The steam. Six to eight minutes in a bamboo basket, and they must go out immediately. A soup dumpling that sits collapses under its own weight.

How to eat one without losing the soup

The liquid inside is genuinely hot enough to burn, and the wrapper tears easily.

1. Lift it by the topknot with chopsticks, supporting the base with your spoon. Do not stab it.
2. Set it in the spoon and let it rest for twenty or thirty seconds.
3. Bite a small hole in the side and sip the broth out.
4. Add a little black vinegar and ginger — the standard accompaniment — then eat the rest in one or two bites.

If a dumpling sticks to the basket and tears, that is the kitchen's fault, not yours: the baskets should be lined with cabbage leaf, cloth or parchment.

Soup dumplings vs. everything they get confused with

Xiao long bao are Shanghainese — specifically from Nanxiang, on the city's edge — not Cantonese, which is why they sit slightly apart on a dim sum menu even though almost every dim sum restaurant now serves them.

What separates a good one

• It holds together when lifted. A dumpling that leaks into the basket was either overfilled or rolled too thin at the base.
• The wrapper is thin but not slack. You should see the filling faintly through it.
• The broth tastes of pork, not of salt. Thin, salty soup means the aspic was made from stock cubes and gelatine rather than skin and bones.
• They arrive hot enough to need waiting for. Lukewarm means they sat.
• The pork is loose, not springy. Overworked filling goes rubbery, which is common when the kitchen is scaling up.

Crab-and-pork versions cost more and are the standard upgrade; they are worth it when the restaurant is good and a waste when it is not, since crab is the first flavour a mediocre kitchen loses.

Where to eat them in the South Bay

Forkelo does not rank soup dumplings yet — the catalog so far covers Vietnamese, Mexican, Japanese and American dishes, and adding a dish means researching it properly rather than listing restaurants. It is a good candidate, precisely because the gap between a well-made xiao long bao and a mass-produced frozen one is enormous and no restaurant rating captures it.

If you are ordering them as part of a larger meal, the beginner's guide to dim sum covers the rest of the table. Every guide is at the guides index, and the explore page lists every ranking built so far.