FROM A TO ZUNI : At This San Francisco Cafe, the Atmosphere Is Earthy and the Chicken Celestial

Two weeks on the road in France, making worthy detours to this and that pillar of gastronomy, and I’ve reached my limits. My sensory control boards are flashing “overload” and the mere thought of foie gras , lobster or truffles--that rich litany of French haute cuisine --is enough to make my head swim. What I really long for is something simple, something with so few ingredients I can count them on the fingers of one hand. As the waiter approaches the table, pad in hand, I’m caught daydreaming, not about the chef’s elaborate menu de degustation , but about . . . roast chicken. Not just any roast chicken, but the celestial version at Zuni.

I picture the big wood-burning brick oven with hardwood stacked beside it. I’m sitting at my favorite table, a long triangle wedged against the windows on Market Street. I can see Zuni’s chef, Judy Rodgers, taking a plump free-range chicken, tucking herbs beneath the skin, then placing it in the oven, close to the glowing embers. When it emerges some 45 minutes later (yes, that’s right; it’s stated right on the menu, and no one is allowed to order the chicken for two until seated), it is roasted to a succulent crisp, slightly smoky from the oven, a taste that I find utterly seductive. The whole bird is carved and presented on a rustic bread, pine nut and dried-currant salad soaked in the bird’s natural juices and doused with a Champagne vinaigrette. It is entirely worth the wait.

Not that waiting is a chore at Zuni. There’s plenty on the menu to interest you until the oven yields your bird. Consider the special oyster list, which offers 19 possibilities, all as fresh and briny as if they’ve just been pulled from the sea. Step outside with the hardy souls taking a cigarette with their aperitifs at one of the sidewalk tables. The oyster man is shucking Kumamoto, Fanny Bay and flat belon oysters in rapid-fire succession at his stand outside the door. Just as at a Paris brasserie, they arrive on a big platter of shaved ice set on a wire stand. Or you can go all out for the plateau de fruits de mers , a series of delectable tastes from the sea.

With chicken still 20 minutes away, it’s time to move on--to the wonderful house-cured anchovies, a Zuni staple. These mild, velvety filets, served with crisp slices of celery and shavings of aged Parmigiano-Reggiano, are delicious enough to overcome even the most entrenched fear of anchovies. The Caesar salad is the real thing, crisp hearts of romaine in a bold anchovy-studded dressing. Rodgers spreads her brandade , a lusty puree of garlic-infused salt cod, on little toasts and browns them in the brick oven. Spying today’s piccolo fritto , a delicate “mixed fry” of artichokes, fennel and onions, I realize there’s just time to slip in an order before the main event arrives.

Next year on Valentine’s Day, Zuni will celebrate its 15th anniversary. Restaurants come and go, but Zuni has become a San Francisco institution, this city’s answer to the French brasserie, where you can eat a snack or a full meal at practically any hour. On Fridays and Saturdays, the place feels like a wildly successful block party in a particularly hip neighborhood. At Saturday lunch, a parade of foodies and Zuni regulars comes for the world’s skinniest fries and distinctive burgers: organic chuck, grilled over hardwood and presented on rosemary focaccia with aioli and house-made pickles. Sundays, there’s often a gathering of off-duty local chefs curious to see just what Rodgers will improvise.

While she may take one idea from French regional cooking, another from the Umbrian countryside and, in the end, rely on what she finds at the farmers’ market to create each day’s menu, Rodgers’ earthy cuisine feels authentic because she knows this food in her bones. Rodgers learned to cook at 16 when she went to France as an exchange student and her host family just happened to be that of three-star chef Jean Troisgros. After a stint at Berkeley’s Chez Panisse, Rodgers made her reputation in the early ‘80s at the Union Hotel in Benicia, where she concentrated on American cooking. That’s where Zuni’s founder, Billy West, discovered her; he persuaded her to become Zuni’s chef in 1987.

One of the big inducements was West’s promise to build the huge wood-burning brick oven that now dominates the kitchen. In her travels in the countryside of France and Italy, Rodgers had fallen in love with the kinds of rustic dishes cooked in traditional wood-fired ovens. Not only pizzas and hearth breads, but the braised meats and casseroles that country cooks would carry to the baker’s oven to cook while they worked in the fields and vineyards. She even roasts cherries and figs in the oven. And, instead of sauteeing her duck confit, she pulls it out of the crock and warms it up in the brick oven to give it a mysterious, smoky edge. Late at night, the cooks will slip terra-cotta cazuelas of oxtail or lamb into the slumbering oven to slowly simmer overnight.

The earthy integrity of the cooking at Zuni is matched by an endearingly eccentric atmosphere. Tables are tucked behind the grand piano, and upstairs is a creaky mezzanine where two dining rooms are joined by a “bridge” of two or three tables with a vertiginous view of the kitchen below--very useful for sussing out what to order. The idiosyncratic brick-and-glass building dates from hasty rebuilding just after San Francisco’s 1906 earthquake and has had bits and pieces added on. As for the mix-and-match decor, it’s clear no big-name designer has ever laid hands on the place.

Zuni has evolved considerably from its beginnings as a modest cafe adjunct to the Red Desert cactus store, when Billy West cooked simple dinners of authentic dishes from Mexico and the Southwest. “One of the cooking utensils was the espresso machine,” Rodgers says. “They used to somehow cook scrambled eggs in the milk steamer.” That’s about the time the late British food writer Elizabeth David, following a delicious scent, discovered West grilling on a Weber in the back alley. Thus began David’s long love affair with Zuni. And through the years, whenever she came to town, she would stop in for a simple meal. If you’re ever impatient at Zuni, it may help to know that even the great Elizabeth David had to wait 45 minutes for her chicken.

Zuni Cafe & Grill, 1658 Market St., San Francisco; (415) 552-2522. Open for breakfast, lunch and dinner Tuesday through Sunday. Full bar. Street parking. Visa, MasterCard and American Express accepted. Dinner for two, food only, $50 to $80.