By Paul Reidinger

FIREFLY CAUGHT FIRE , so to speak, almost the instant it opened 11 years ago, in the fall of 1993. The restaurant had been conceived as a neighborhood spot, in a neighborhood (toward the top of 24th Street in Noe Valley) then notably short of places to eat. The young proprietors, Brad Levy and Veva Edelson, did much of the cosmetic makeover of the old La Roca space themselves, and there was an appealing threadbareness to things. Firefly was a labor of love.

Then, within weeks of the restaurant's launch, down swooped old Jim Wood of the San Francisco Examiner. He exclaimed over Levy's American-but-ethnic food (Levy had cooked at Embarko in South Park), and Firefly abruptly went from being a neighborhood restaurant that had barely opened its doors to being an overstuffed destination spot the neighbors often couldn't get into. On weekend nights in the mid-1990s, parking was impossible for a number of blocks in every direction, and those wicked little DPT carts circled, sped, and skulked, waiting for some impatient or indifferent diner to block a driveway so a tow truck could be summoned to complete its dark mission before dessert.

But, as anyone who's ever lighted a charcoal grill knows, fires have stages, and the initial leaping flames at some point become a radiance that's less spectacular but hot and steady and suitable for cooking in a way brightly flickering tongues are not. These days Firefly glows in that muted but intense, sustaining way; it is busy but not insane, it's full of neighborhood people (most of whom have walked – the great urban luxury of our time), the food is as good as ever, and the temper of the place retains its balance of hip youthfulness and knowledgeable professionalism. It is everything a neighborhood restaurant in San Francisco should be and a reminder of the long-established truth that some of the best places to eat in this city are far from the hotels and convention halls in the city center.

Levy's menu continues to rely on elements of long standing – among them shrimp-and-scallop pot stickers ($4.50 for two), which have been continuously offered since Day One, and a discreet commitment to vegetarian choices – while gracefully folding in bits of evolution. The most conspicuous of the latter is a $29 fixed-price option (available Sunday through Thursday), which brings a choice of starter, main course, and dessert, with coffee or tea. Generally I find these sorts of deals irresistible, but I did some silent number-crunching and came to the conclusion that I would be no better off with the prix fixe and would, moreover, be committed to dessert, which is not the worst fate in the world but not always the best, either.

Elsewhere around our table, though, the prix fixe found its share of takers. It's likely to save you at least a few bucks, for one thing, and it seems to provide a certain rigidity of form people find reassuring. Also, it grants you de facto permission to eat more, though it's hard to imagine getting fat on any Firefly diet. The food is generous and occasionally rich, but even a dish as potentially engorging as pork osso buco ($17.50), served with a pesto polenta bar and a classic, rusty water-colored osso buco sauce (wine, stock, carrots, onions, tomatoes, lots of simmering), relies for its effect mainly on big, boldly illuminated flavors rather than big calories.

The same technique works just as well on dishes that are less heavy to begin with. A stack of heirloom tomatoes ($8.75) combines the sweetness of the late-summer fruit with the salty-sharpness of cubed feta cheese and the smokiness of grilled onions. A halibut filet ($18.50) hits the grill with a thick coriander crust and is then plated with a roasted-tomato sauce and a pat of mashed potatoes sharpened with celery root instead of fattened by a half pound of butter. Even a modest salad of organic greens ($6.50) carries a kick: spicy almonds bathed in a champagne vinaigrette.

One test of vegetarian dishes on an omnivore-oriented menu is whether omnivores even recognize that a given dish is meatless. The confirmed omnivore to my right seemed quite pleased with his quite spicy scarlet-runner-bean chili ($15.50), which arrived in company with a cheese-stuffed, delicately battered chili relleno, a splash of pico de gallo, and crisp-fried plantain disks. He plowed through it all with evident satisfaction, and if he noted the lack of animal flesh, he didn't say so and showed no sign of being bothered.

To my left, meanwhile, a more consciously vegetarian-inclined companion dug into a Thai-style coconut curry ($14.75), with grilled Japanese eggplant and ground seitan, the latter providing a weight and texture very much like that of some sort of ground meat. On the seitan issue I am a fence-sitter, but in this case I liked it because it served simply as a beast of burden, carrier of the powerful – and, to me, delightful – sweet-sharp perfume of the curry.

Pastry chef Kate Curnes's desserts are homey, with nice seasonal touches – a mix of blueberries and raspberries, say, to accompany toasted brown sugar angel-food rings ($7). There is an impeccable crème brûlée ($7), scented with lemon and accompanied by candied lemon peel, and a quite rich mocha ice-cream sandwich made with chocolate cookies. The last turned a bit runny in the fiery evening heat, but we managed to gobble it down before making the short walk home.

Firefly. 4288 24th St. (at Douglass), S.F. (415) 821-7652. Dinner: nightly 5:30-10 p.m. Beer and wine. American Express, MasterCard, Visa. Slightly noisy. Wheelchair accessible.