Dec. 04–Judy Rodgers, chef and co-owner of the famed Zuni Cafe, and a visionary who helped define San Francisco cuisine, died Monday night after a yearlong battle with cancer of the appendix. She was 57.

Renowned as one of the most influential American chefs of her time, Ms. Rodgers proved through her rustic, urban fare that food could be sophisticated without being fussy.

A revered mentor and teacher, she inspired chefs around the country with her ingredient-driven style and pioneering techniques.

“She was a force to be reckoned with,” said Gayle Pirie, the chef and co-owner of Foreign Cinema in the Mission District, who worked under Ms. Rodgers for nearly seven years at Zuni.

“She had an amazing palate, an incredible brain and an impeccable vision.”

Ms. Rodgers put Zuni on the map when she took over the kitchen in 1987, introducing straightforward dishes like roast chicken for two and espresso granita. Her approach and cooking style earned her and Zuni coveted awards from the James Beard Foundation — best chef in California in 2000, best restaurant in 2003 and best chef in the U.S. in 2004.

Unexpected start

Born and raised in St. Louis, Ms. Rodgers began cooking almost by accident.

Interested in spending time abroad, her neighbor helped arrange for her to do her junior year in high school in France, where she would stay with his friends in Roanne, about 200 miles southeast of Paris. Those friends happened to be the Troisgros family, who owned the Michelin 3-star restaurant Les Fr?res Troisgros.

Urged to document her trip, Ms. Rodgers stood at the side of Jean and Pierre Troisgros each day after school, watching intently, recording recipes and tasting at every turn.

In her award-winning “Zuni Cafe Cookbook,” published in 2002, Ms. Rodgers recounted the experience.

“It was not just the best food, it was also the simplest and purest, and the restaurant the most convivial,” she wrote. “The seasonality and regional character of the food, coupled with lack of pretension, brought clients back.”

It was a philosophy that would guide her in the kitchen at Zuni, though that was still far in the future.

Originally studied art

When she returned from France in 1974, Ms. Rodgers focused on her studies in art history at Stanford University. But in late 1977, she stumbled upon Chez Panisse, where Alice Waters was practicing much of what Ms. Rodgers had seen in the Troisgros kitchen.

Armed with her notes and recipes from France, she was given the opportunity to cook the lunch shift at Chez Panisse, where she stayed for much of the next two years.

“She came from that same intellectual, historical place to food, and an artistic place as well,” Waters recalled.

“She loved simple country cooking, but she had the understanding of a very sophisticated kind of cooking as well. That’s sort of rare.”

Waters said she ran to try Ms. Rodgers’ cooking at her next restaurant job, at the Union Hotel in Benicia. The food was decidedly American, and Ms. Rodgers made a name for herself with impeccable versions of fried chicken and biscuits.

Ms. Rodgers eventually left Benicia to travel to Italy, then returned to the U.S. as opening chef for Yellowfingers restaurant in New York. She came back to the Bay Area in 1987 after Billy West, who had opened Zuni Cafe in 1979, made repeated trips to New York to lure her back.

Unusual demand

But before she accepted the job, she insisted that West add a wood-fired brick oven to the funky space that still houses Zuni.

He agreed, and that oven became the restaurant’s focal point and cooking method for many of the iconic dishes that remain on the menu today, most notably the roast chicken.

Pirie witnessed the transformation of the restaurant under Ms. Rodgers, who slowly added simple, rustic dishes that were not the norm.

“In San Francisco we were still grappling with more continental, fusion cuisine that was really fancy,” Pirie said. “Here comes Judy, and she was going to put the perfect persimmon on a plate with prosciutto, which took guts. She was going to barrel through, and put the best, and purest, on show.”

It was similar to what Waters was doing across the bay at Chez Panisse, but with a more urban, sophisticated twist.

“I remember the first time I went there to eat, and I was so jealous,” Waters said. “It was so good, and the menu looked like everything I wanted to eat, and hadn’t thought to put on our menu.”

The combinations were classic but inspired — celery and anchovies; dates and Parmesan; pillowy ricotta gnocchi with accompaniments to reflect the season — and revolutionary in their simplicity.

“She was a perfectionist,” said Joyce Goldstein, a San Francisco chef, author and consultant. “She didn’t need a huge variety of things on the menu. She didn’t need to be daring. But she did everything perfectly.”

Ms. Rodgers also made a point of avoiding the limelight.

“You could dine at Zuni 100 times and never see her,” said Gilbert Pilgram, Ms. Rodgers’ partner at Zuni. “But she was always, always behind the curtain.”

Self-taught scholar

Colleagues and fellow chefs also noted her near-perfect palate.

“I thought she had the best mouth in the business,” Goldstein said. “She was self-taught and she knew the importance of tasting, tasting, tasting.”

That filtered down to her disciples, who said her ability to teach was among her best attributes.

With her cookbook, which took a decade to write, “she gave the world her sense of instruction, which was warm and gracious and not arrogant,” Pirie said.

Ms. Rodgers is survived by her husband, Kirk Russell; her mother, Cathy Rodgers of St. Louis; a sister, Carolyn, of Boston; a brother, Doug, also of St. Louis; and two stepdaughters.

The family plans a private memorial service. An invitation-only celebration of Ms. Rodgers’ life is tentatively scheduled for Feb. 10 at Zuni Cafe. It will coincide with the restaurant’s 35th anniversary.

Amanda Gold is a San Francisco Chronicle staff writer. E-mail: agold@sfchronicle.com