After scouring the menus to no avail, I described Lion's Head to two servers at this favorite mainly Northern Chinese place in Waltham. They decided that what I was looking for was the dish listed as Jumbo Meat Ball Casserole.
What I got was three very tasty meatballs, but not the gigantic (fist-sized) specimens I expected (maybe scaled down for lunch?) They were more squash-ball sized, but gingery and served on a bed of choy, quite delicious.
The server suggested that if I liked Shanghainese, I should check out Shanghai Gate; my tip to her was New Taste of Asia.
I'm going to have to start studying up on my Chinese menu characters again.