Molly O’Neill frequently called food writing her “Plan B.” In truth, it was more like her Plan C. She originally wanted to be a poet and a painter but settled into the restaurant industry even before enrolling at Denison University in nearby Granville, where she studied painting and writing. She would spend a decade in professional kitchens, going toe to toe with men, earning their respect while rebuffing their flirtations and sexist remarks.

She became an accomplished chef in a period of male-dominated kitchens and an award-winning food journalist and cookbook author who championed immigrant home cooks long before Anthony Bourdain and Andrew Zimmern. She died June 16 in her apartment in Manhattan. She was 66.

The writer’s death was confirmed by her friend Mame Kennedy, who said Ms. O’Neill had been battling various illnesses, including adrenal cancer, for several years.

A native of Columbus, Ohio, who grew up in a home obsessed with baseball, Ms. O’Neill started cooking in her youth. She secretly prepared meals for her five brothers who had grown tired of their mother’s healthful dinners, often prepared with ingredients from a local farm. Ms. O’Neill first learned to cook by watching women at the grocery store prepare “hamburger bun pizza with wiener pepperoni and Velveeta cheese” in makeshift demonstrations. She used those lessons to cook for her brothers when her parents were away, preparing “cheesy manwiches” and chocolate pudding cake and that hamburger bun pizza.

“We would then fumigate the house and cook the casserole that had been prepared for us or bake off the fish,” only to throw out the meal, Ms. O’Neill told a Smithsonian audience in 2010. “We would leave the smell in the house so that when my parents walked in, everything appeared to be in order. I mean, they should have been happy. Other kids were doing drugs. We were doing these pizzas.”

Ms. O’Neill’s cooking career took her from Columbus to Northampton, Mass., where she and eight like-minded friends founded Ain’t I a Wommon Club in 1977, a feminist restaurant specializing in “nonviolent cuisine” that rejected “the violence and maleness of meat eating,” according to Ms. O’Neill’s 2006 memoir, “Mostly True: A Memoir of Family, Food and Baseball.” Some of the club’s practices presaged restaurant movements of the 21st century, including policies that banned tipping and allowed diners to pay according to their means.

Ms. O’Neill formally studied cuisine at La Varenne in Paris, which offered cooking classes in French and English. Her skills eventually led to an offer to take over the kitchen at Ciro & Sal’s, a respected northern Italian restaurant in Boston. In 1982, she won the award for “Best Chef, Female”, from Boston magazine in its annual Best of Boston issue. She also befriended two women who became mentors, Julia Child and Lillian Hellman. It was Hellman, the playwright behind “The Little Foxes” and other celebrated Broadway melodramas, who gave Ms. O’Neill some practical advice about writing for a living.

“She was prone to outbursts and scathing tirades, and she scared me as much as fifty meals ordered all at once,” Ms. O’Neill wrote in “Mostly True.” “I quickly lost the dreamy reverence I’d always had for words and began to see them as ingredients. By the time the Boston Globe called and asked me to write a story about pancakes, the boundaries between art and commerce seemed more porous.”

Ms. O’Neill invested the same passion in her writing as she did with her cooking. For what was to be a 300-word story about pancakes for the Globe, she researched historical cookbooks, various stirring techniques and maple syrups to test 50 batters. She transformed her project into a 3,000-word opus that the Globe editors loved. She went on to write for Boston magazine, whose editor Donald Forst would leave the publication to become the first editor of New York Newsday, where he hired Ms. O’Neill as restaurant critic.

Five years later, Ms. O’Neill was hired by the New York Times, and she spent a decade at the Grey Lady reporting on the food industry and writing a column for the paper’s Sunday magazine. Her writing for the Times ranged from a Sunday front-page story about genetically modified foods in 1992 to a recipe for Thai cucumber and mint salsa, which accompanied her story on how salsa had surpassed ketchup to become the “king of American condiments.”

Ms. O’Neill wrote numerous cookbooks, including “The New York Cookbook” (1992), “A Well-Seasoned Appetite” (1995), “The Pleasure of Your Company” (1997) and her magnum opus, “One Big Table” (2010). For “One Big Table,” she and assistants hosted potluck dinners across the United States, asking people to bring a dish and recipe as well as a donation to the local food bank. In all, they held 150 potlucks and gathered more than 7,000 recipes, only two of which appear in the cookbook.

“At the end of a total of eight years,” Ms. O’Neill told the Smithsonian audience, “I had what was a perfectly balanced, demographic portrait of American food. It was the most boring book I could have imagined, and that was a devastating discovery.”

Ms. O’Neill realized she had followed the numbers, not the passion, so she essentially started over and sought out some 600 recipes from visionary African American artists, Vietnamese communities in New Orleans, survivalist groups and countless others. “I was looking at what we held in common, not what distinguishes us,” she said at the Smithsonian.

Her work as a food journalist earned her three James Beard Awards, including one for her job as host of the PBS series “Great Food.” Ms. O’Neill went on to found CookNscribble, a group to nurture young and established food writers via workshops, online courses and mentorships. She was always urging food writers to treat their jobs more like hard-news journalists, not feature reporters who too often pander to PR agents.

Molly O’Neill was born Oct. 9, 1952, the oldest child — and only daughter — of Charles O’Neill and the former Virginia Gwinn.

Her father had played minor league baseball and fostered a love of the game among his offspring. The youngest, Paul O’Neill, enjoyed a 17-year career in Major League Baseball, including five seasons as an All-Star. When he was traded to the New York Yankees in 1992, his only sister was ecstatic to live in the same city as her brother, whom she had adored since he was an infant.

“Heck, I potty-trained the guy,” she joked with a reporter.

Ms. O’Neill’s marriages to Stanley Dry and Arthur Samuelson ended in divorce. Survivors include her mother, of Ohio, and five brothers.

Ms. O’Neill never lost her passion for writing about food, even as she started to get sick and had to move from her home in Rensselaerville, N.Y., to an apartment in New York for medical treatments. She had a liver transplant in 2016.

A pa­thol­ogy report on her old liver revealed some cancerous cells, which had metastasized to her adrenal glands. In 2017, her friends and fans donated more than $100,000 to help with her medical expenses. Ms. O’Neill had been working on a book about her liver failure and her battle with cancer up until the day she died.

“She really wasn’t ready to go,” says her former Rensselaerville neighbor Kennedy. “She had a lot of living left to do, as far as she was concerned.”

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