The Yang's Fry chain is, if not the originator, then clearly the benchmark for Shanghai's homegrown pan-fried pork dumpling, the shengjian bao. They're a stone-cold Shanghainese street food classic, and a cousin to Shanghai's more famous soup dumpling, the xiaolongbao. The puffy dumplings, with a thick, bready skin sprinkled with sesame seeds and chopped spring onions, are shallow-fried in wide black pans. Lines are long and the liquid inside the dumplings is hot as hell. Careful. You order by the liang -- a 50g unit that amounts to four dumplings.