Mexican cookbook author Diana Kennedy is the diva of doing it right

"You should never use these yellow-brown onions," declares Diana Kennedy as she chops into one during a cooking demonstration at Seattle's Palace Ballroom. "They're too sweet. Use a medium white onion instead; it has much more onion flavor."

Then she reaches for a tomato.

"You want the whole tomato," she says, her precise punctuation still redolent of her English upbringing, even though she has lived in the United States and Mexico for more than half a century. "Use the skins, the seeds, the juice; don't do that French thing," she commands, presumably referring to the technique of dicing a peeled tomato and discarding the seeds and pulp. "It's ridiculous."

She moves on to serrano chilies, quartering them lengthwise and chopping them roughly. "If you have a book that tells you to remove the seeds and the white membrane from your chilies, then you know that the author doesn't know what the devil she's talking about and you can throw that book away."

"What is this?" she demands when Palace executive chef Eric Tanaka passes her the ricotta cheese called for in the recipe she's making. "This is not ricotta; I don't know what this is. Ricotta — requeson — is what you get when you recook the whey left after making queso fresco. It's all in the book somewhere. You should read it. Honestly. I don't know how you people put up with the food you get in the shops."

"How do you put up with corn that's as sweet as custard?" she demands of no one in particular.

How does this burner work?" she asks Tanaka.

"I might not know how to chop an onion or buy ricotta," he says good-naturedly, "but I do know how to light these burners." Tanaka, who picked up a James Beard Award in 2004 for Best Chef in the Pacific Northwest, knows more than he lets on.

"I don't mean to be so ornery," Kennedy says. "It's just part of my persona. The New York Times ran a story last week about how impossible I am, demanding authentic ingredients and things like that. But my stubborn nature sells a lot of cookbooks."

Kennedy is a stickler for authenticity, all right. A recipe writer and cookbook author of uncommon precision, she is notoriously impatient with inferior ingredients and intolerant of shortcuts that undermine a dish's unique character

"The first time I was in Seattle," she continues, "it was 1956, and this was a real hick town. You couldn't get anything here. But now there's no excuse. There has been a complete and utter transformation, and you can get absolutely anything here." Tanaka raises his shoulders in the universal gesture of uncertainty.

"Really," insists Kennedy. "There is no excuse."

Kennedy's first trip to Seattle must have come shortly before she moved to Mexico in 1957 with her husband, Paul Kennedy, who was a foreign correspondent for The New York Times. After Paul died in 1967, Times food editor Craig Claiborne persuaded Kennedy to start teaching classes on Mexican cooking in New York City. This led to several years of traveling throughout Mexico to research regional cooking there, and to her first book, "The Cuisines of Mexico," in 1972.

At the Palace Ballroom in Seattle, Kennedy resigned herself to the state of the ricotta cheese and stirred it over a low flame. "Any Mexican cook will tell you that you will know when a dish is done because the food will tell you. There are no shortcuts."

"I finished a book recently on Oaxaca," she said. "And my editor wanted to know, 'Do you really have to include instructions on how to clean an iguana?' I said yes, of course I do. I just don't know what's happening to our food! But it's stupid; all this low-fat nonsense. Why would you want to cut out fat? What kind of person would want a boneless, skinless chicken breast when you could have a proper chicken?"

All this emphasis on authenticity has not gone unrewarded. For promoting understanding of Mexican culture in the English-speaking world, she was awarded Member of the British Empire status from Queen Elizabeth, and the government of Mexico has awarded Kennedy the Order of the Aztec Eagle, the Mexican equivalent of knighthood.

By any measure, Diana Kennedy is a formidable woman. But the dishes in her book are relatively simple to prepare, as long as you take time to procure the right ingredients and follow her detailed instructions. "The simplest food," she writes in the latest edition of her classic, "The Art of Mexican Cooking," "is always the most difficult to prepare, for there are no predominant flavors to mask bad or indifferent ingredients or the careless handling of those ingredients."

Greg Atkinson is a chef instructor at Seattle Culinary Academy. He can be reached at greg@westcoastcooking.com. Erika Schultz is a Seattle Times staff photographer.

Requeson Revuelto a la Mexicana

Makes 4 servings

This dish is both simple and sublime. Serve it with soft corn tortillas for breakfast or lunch.

4 tablespoons safflower oil

1/3 cup finely chopped white onion

4 to 5 chilies serranos, finely chopped

1 ¼ cups finely chopped unpeeled tomatoes

2 ½ cups (about 1 pound) ricotta cheese

½ teaspoon sea salt, or to taste

1. Heat the oil in a frying pan; add the onion and chilies and fry gently without browning for 1 minute. Add the tomatoes and cook, stirring from time to time over high heat until the mixture is fairly dry, about 5 minutes.

2. Add the ricotta and salt and mix well. Cook, stirring over medium heat until the ricotta is golden and the mixture comes away cleanly from the sides of the pan.

— Adapted from "The Art of Mexican Cooking" by Diana Kennedy