With thanks to Kat for using the Chinese name, I've finally got a clue to what NY chowhounds have been talking about when they say "soup buns". These are the small steamed baozi with the twisted topknot.
I've had xiao long bao at Din Tai Fung in Taipei (which proudly posts the NY Times review proclaiming its x.l.b. as the best in the world) and while these were certainly juicy, I don't think of them as soup-filled. Nip and slurp was the eating protocol, but the "soup" was more like the steamed meat juices, rather than a rich broth. Ditto for the xiao long bao I ate for breakfast every day my first visit to Shanghai in 1983. [If I could find my photos from the trip, I'm sure there are some taken through a doorway of thousands of baozi being wrapped or a bicyle delivery man peddling down a narrow alley with a stack of 2' wide steamers piled 10 high on the handlebars.]
How much liquid is in a soup bun? Are these a special kind with extra soup added? A NY Shanghai variant?