Like the stories behind many Chinese dishes, the history of xiao long bao is swathed in folklore. Many cities in the Yangtze River Delta, such as Hangzhou and Wuxi, claim it as their own.

This is the only place we know of that has Hangzhou pork mini buns. Wrapped in a denser, more breadlike wrapper than xiao long bao, they also differ filling-wise. While both use a pork meatball ...