SAN FRANCISCO – What do you eat when no one is watching?

That's the question Patrick McFarlin asked of folks he didn't know, to start a conversation. They were mostly people in his wife's world: chefs, culinary professionals, scholars and food writers. Their answers were so surprising and delightful that McFarlin recorded them in a small journal. He filled up one notebook, and then another and another.

One foodie admitted pouring sardine juice over cottage cheese when dining alone. Another ate oyster crackers in coffee, and someone else confessed to crumbling saltines into milk.

McFarlin forgot about the journals until his wife, chef and cookbook author Deborah Madison, discovered them years later in their New Mexico home.

"I asked Patrick, 'What are these strange food things?' and he reminded me that he had asked this question. I thought they would make a fun book," says Madison, who is coming to speak in her hometown of Davis on Saturday.

"These were all food professionals, and it's funny that, despite what we know about nutrition and health, when we're eating alone, when we're on your own, a whole other thing comes out that doesn't necessarily relate to our personas."

The couple went on to interview cooks, farmers, artists, writers, friends, strangers, young people, old people, the widowed and those involved in relationships.

They turned the collection of culinary confessions into "What We Eat When We Eat Alone: Stories and 100 Recipes" ($24.99, Gibbs Smith, 272 pages), written by Madison and illustrated by McFarlin.

The book is about "a secret life of consumption born out of the temporary freedom – or burden, for some – of being alone. There are foods so utterly idiosyncratic that they would never, ever be shared with another, and there are some very ambitious undertakings."

"I don't really see this as a cookbook," Madison says. "Yes, there are recipes, but they're not driving the book. It's about people."

It's about people who, on their own, will eat bread soaked in margarita mix, hot dogs boiled in riesling, Grape Nuts on ice cream, and peanut butter and pepper-bacon sandwiches. They'll use leftover spaghetti for a sandwich, or fry up day-old spaghetti with Swiss cheese.

Sometimes these choices are nostalgic, a longing for a favorite childhood treat, or the chance, when alone, to enjoy a quirky dish not favored by the family.

And, the couple says, our eating-alone food "is not always consistent with those sides of ourselves that the world sees."

A short homecoming

Madison and McFarlin are in the Bay Area for a few days and will dine at least once at the famed vegetarian restaurant Greens, where Madison was the founding chef nearly 30 years ago.

They will return home to New Mexico, and then Madison will be back in California on Saturday for a book-signing in her hometown, Davis. She'll be at the Avid Reader, 617 Second St., at 4 p.m.

She was born in Connecticut and grew up in Davis, where her father fed the family from his fruit orchard and vegetable garden. She attended the University of California, Davis, for two years and transferred to UC Santa Cruz, where she studied sociology and city planning.

After college, in the late 1960s, she worked in the kitchen at San Francisco's Zen Center, and when the center opened Greens in 1979, she stepped in as chef. Greens still serves some of her creations, such as the black-bean chili.

She seldom gets back here.

"I don't know how to drive in San Francisco anymore," she laughs.

Madison has written a plethora of vegetarian cookbooks, including the award-winning 1997 "Vegetarian Cooking for Everyone." She is not a vegetarian but "a vegophile."

"I love vegetarian food, and we eat it a lot, but not exclusively," she says.

Love despite pizza and okra

Madison and her husband recently celebrated their 19th wedding anniversary. Both have June birthdays.

He grew up in Little Rock, Ark., and introduced a horrified Madison to take-out pizza when they were dating. She was in her 40s, and had never seen a take-out pizza. Then he made her fried okra for breakfast.

Call The Bee's Dixie Reid, (916) 321-1134.