By Paul Reidinger

A TRUISM TEACHES that you can never put your foot in the same river twice. Neither, by the same logic, can you ever visit the same restaurant twice, not really, for at the very least the crowd will be different, and at the very most the restaurant, in the interval between visits, will have become some other restaurant or no restaurant at all. The restaurant writer accepts this fluidity as part of the nature of things while never being entirely free of curiosity about the course of this or that place visited, considered, commented on; sometimes word filters back that a certain restaurant has hired surly servers or jacked up its prices or run afoul of the health department, and one is tempted to go back and assess – but going back is a luxury in an environment filled with constantly onrushing tomorrows.

Recently I permitted myself the luxury of returning to Delfina, Craig Stoll's Tuscan-minded spot on 18th Street just east of Dolores Park. When Delfina opened toward the end of 1998, it was a sliver of a restaurant, like a hallway set with a few tables and a kitchen at the rear, but in a neighborhood then starved for restaurants and high food culture generally, it was an eagerly welcomed sliver. Stoll, moreover, had lived in Tuscany and brought a scholarly intensity to the food; Delfina might have been conceived as a neighborhood restaurant, but almost immediately (like Firefly a few years earlier) it was set upon by wandering bands of the food savvy, who knew the real deal when they tasted it.

Over the years I have often heard and read about Delfina. It became, in the national food press, the perfect San Francisco neighborhood restaurant, known only to the cognoscenti, which quickly came to mean just about everybody. Celebrities – many of whom I had never heard of subsequent to my divorce from pop culture – were said to frequent the place. And, a few years ago, there was an expansion into a neighboring storefront that, it turns out, has more than doubled the size of the restaurant. The original narrowness is now a handsome wine bar, while the dining room has opened out to the east, beyond a set of waferlike pillars.

Delfina breathes easier now. The sound level, which was for me so overwhelming an issue in the original incarnation – a tiny space done up L.A.-style in hard surfaces, with an echo-chamber din that made conversation difficult – has been expertly balanced so that the pleasant ambient clamor does not invade the hushed bubble at each table. One notes the sound-damping materials discreetly deployed above the window transoms and behind the banquettes, and also the wood floors and more generous spacing between tables. There is still enough noise to reassure the hubbub-hungry young, and at the same time I would not hesitate to take my parents there. As for the overall look: it's Italian-urban, Milanese, a harmony of wood, glass, steel, zinc, and candlelight, both venerable and ultramodern, and surprisingly warm.

One aspect of Delfina that hasn't changed – perhaps because changing it much would be an idle exercise – is the food. This is not surprising, given the combination of Stoll's expertise and his constant, roving presence throughout the restaurant, not least in the kitchen. He does have a plan to open a pizzeria, and that could be a distraction, but for now he's on hand in the manner of the true top-drawer chef-owner. Meantime, while the pizzeria plans mature, the restaurant gets some of its divine bread from Tartine, the bakery a few steps away at the corner of Guerrero Street that probably wouldn't be there at all if not for Delfina.

Other Italians refer to Tuscans as mangiafagioli – bean eaters – so beans of various sorts are all but omnipresent on Delfina's menu, at least in winter. Sometimes they aren't even announced – appearing as, say, a butterlike puree on crostini topped with briny Monterey Bay sardines. Sometimes they aren't even there: petrale sole ($17.75) baked in a parchment bag (which swelled up as if with microwave popcorn and had to be cut open) contained, in addition to the flawlessly tender-firm fish in a butter-and-white wine bath, potato coins and shreds of fennel root whose licorice breath had been muted to a ghostly suggestion.

But, generally speaking, beans are present and accounted for. Smallish white ones turn up as a bed for tenderly grilled calamari ($8.25) – beware the unpitted olives – while large, flat cannellini beans provide a floor for Hawaiian ahi ($18.75), grilled medium rare and served with more assertive grilled fennel root and a dab of sweet-tart Meyer lemon relish.

Desserts, at $6.75, aren't particularly pricey as desserts in such restaurants go, and the profiteroles, stuffed with espresso ice cream, are a massive platter of chocolate-slathered pastry that amounts to quite a good deal, if one dismisses caloric concerns. The signature dessert remains, as it has been from the beginning, buttermilk panna cotta: a snow-white, slightly tapered column of cooked custard given an almost citruslike pucker of acid by the buttermilk and sparingly decorated with a scattering of rubylike pomegranate seeds and a light drizzling of a lightly caramelized sugar syrup. It is, in the best Italian – and Delfina – tradition, a dish that cannot be improved upon. Truly.