By Paul Reidinger

THERE USED TO be, not so very many years ago, a kind of vertical integration in gay restaurants: Such places were understood to be gay in the way that certain bars were – from top to bottom, you might say. The clientele was gay; so was the (flirty) staff and the (often campy, sometimes disco-like) atmosphere. Also, sadly, the (grim) food. In these establishments, for all their blemishes and shortcomings, one could briefly but completely escape the gravity field of heteroland.

If gay seems to have become slightly passé of late – dissed on the one hand by the young, who prefer new or no labels, and ignored on the other by the flood of rich hetero immigrants who since the late 1990s have transformed this once bohemian city into a precinct of urban suburbia with monster houses and countless babies – then at least one blessing of the shift is the advent of a postgay restaurant like Thai Chef, which opened recently in the heart of the Castro (only steps, in fact, from Harvey's, the heart of the heart of the Castro).

Thai Chef meets many of the old criteria for gay restaurants. It is in a gay neighborhood. A sizable majority of the patrons, judging from the many tablesful of same-sex couples, are gay. The waitstaff consists almost entirely of handsome young Thai men in tight black T-shirts: a look very Studio West, circa 1980. The decor is modern urban chic, an appealingly spare blend of teak, black steel, and suspended cylinders of light that look like glowing candles. And yet ... Thai Chef has none of that old-time, closed-loop, homos contra mundum feel. It is a neighborhood restaurant full of neighbors. Even better: the Thai food is nothing short of exceptional in the freshness of the ingredients and the confidence with which they're handled. Gay might belong to yesteryear, but, as Thai Chef proves, so too does the longtime dominance in local Thai cookery of Thep Phanom and Manora's.

A favorable portent to any meal is the papaya salad ($6.95), a bale of finely shredded papaya and carrot drenched in a lemon dressing whose sweet-tartness gives the dish an identity similar to, though slightly more honey-tongued than, sauerkraut. Tomato quarters and green beans bring color, chiles a bit of heat, and ground peanuts plenty of textural contrast. A silver-noodle salad ($7.50) is at first blush quite similar; the noodles are comparable in proportion to the papaya shreds, but they are more rubbery and slippery (hence trickier to capture with chopsticks; forks are discreetly omnipresent for the frustrated and/or inept), and the salad also includes chicken or shrimp for some added heft.

If fish cookery is one of the chief standards by which to judge a kitchen's proficiency, another is (for me) its handling of eggplant – a turbulent vegetable with a tendency to become soggy and bitter. An obvious palliative is to use, as Thai Chef does, one of the Japanese-style eggplants when making a dish like pad ma kuer ($6.25). These Asian variants not only have a pretty purple-violet color but are much more slender, like zucchini, which means they retain an attractive density when chunked, sautéed, and tossed with black-bean paste, garlic, chiles, and basil. The resulting sauce, something of a standard in American Thai restaurants, shows many of the characteristics of good red wine: its flavor is deep and slightly smoky, with hints of pepper, fruit, and honey. Even good eggplant needs all the help it can get, and the black-bean sauce is all about help.

Of course there is fish too, but the seafood offerings tend to emphasize shellfish, as in the seafood clay pot ($12.95), a glazed earthenware casserole filled with prawns, bay scallops, and mussels, along with calamari, cod cubes, and coins of zucchini and carrot, all of it bathed in a red curry broth that simmers on the verge of being incendiary. And while the menu is conspicuously vegetarian-friendly, there is plenty of poultry and meat – and, in the case of barbecue ($8.95), really nothing but meat, a heap of thinly sliced beef (or chicken or pork if you prefer) marinated and quickly grilled, crisping the edges while leaving the middles juicy and tender.

At the other, no-meat end of the spectrum we find a cornucopia. Almost every dish on the menu is available in fleshless guise, including spicy noodles ($6.25), with seared tofu replacing the standard version's chicken, beef, pork, or shrimp, while the electrifying sauce – of chiles, onions, garlic, tomatoes, and basil – remains the same. Still, there are some dishes that resist the vegetarian imperative, among them pad kee mao ped ($8.95), egg noodles with shredded duck meat and bamboo shoots in a sauce of tomatoes, basil, onions, and chiles; not only is a vegetarian version not offered, no other version is offered. And just as well, since the richness of the duck is like a steadily thumping bass line beneath the treble brightness of the sauce – like disco music on a plate, in a way (disco duck?), except that disco is as passé now as the gay culture it was a central part of. I miss disco, sort of, but I'll take the duck.

Thai Chef. 4133 18th St. (at Collingwood), S.F. (415) 551-CHEF, www.thaichefsf.com. Sun.-Thurs., 11 a.m.-10:30 p.m.; Fri.-Sat., 11 a.m.-midnight. Beer and wine. MasterCard, Visa. Moderately noisy. Wheelchair accessible.