The flagship joint of the An family crab dynasty, Thanh Long, is still the best of all their San Francisco restaurants (and probably California too!). The biggest, sweetest crabs available are prepared in only three simple ways: roasted, “drunken” (marinated in wine, sake, and brandy), and tamarind. The most downscale of the small group of restaurants owned by the Ans (which includes both San Francisco and Los Angeles versions of Crustacean), Thanh Long is no-nonsense. Diners range from traditional Vietnamese families to out-of-towners on a quest for the best crab in the city. Servers offer classic unobtrusiveness, as well as efficient cleanup of the ever-growing piles of messy plates. Several dishes come out of the “Secret Kitchen,” to which only certain staff have access. No matter what else you order from the extensive Vietnamese menu, do not miss the garlic noodles, made from a legendary-and, of course, secret-sauce.