During many business trips to Shanghai I often had baby bok choy that was served in a thin (unthickened), pale yellow sauce or broth - common in restaurants in Shangai. Very delicious! What kind of sauce would this be? It had a nice flavor, but not distinctly lemony or chicken-brothy or anything I could identify. And how can I cook it this way? Thanks!
I've never cooked or eaten in Shanghai, however, based on a rudimentary knowledge of Chinese cooking, cooking it at home, and with the support of Google, I would guess the following:
Bok choy is blanched for a short time in boiling water, and then refreshed in an ice bath.
It is stir fried in a very hot wok, probably with some garlic.
A slurry of cornstarch is added. It is made with water, soy, perhaps some sesame oil. This produces the light sauce.
I suspect that sometimes, fermented black bean might be added.
Baby Bok Choy. Is that with the green stem. There is more than 1 type of Bok Choy. It is dropped in boiling salt water for Shanghai stile. About 40 seconds till bright green. Then drained. Sesame oil is used as the base with soy sauce, corn starch. What ever else.It is then glazed in that sauce. 100 ways to make this. So boiled in salt water, green stem Bok Choy, sesame oil used. Shanghai stile. What sauce you had I do not know.
The most common way to cook leafy vegetables in most of southern and southeastern China is probably stir frying, so I'm afraid it's just the liquid left from stir frying (for some reason, the liquid might have been thickened using starch, but that's not very common). It could also be Chinese broth, which wouldn't taste chickeny because the main ingredients would be Jinhua ham and pork bones.