Chef Tom Valenti learned to cook from his Italian grandma, Settimia. His modern holiday menu shows her influence, from the pancetta in the soup to the garlic gravy on the bird.

Growing up in Ithaca, New York, "a coddled, overfed little prince of an only child" by his own description, Tom Valenti, the chef and owner of Ouest on Manhattan's Upper West Side, remembers the Thanksgivings of his boyhood as wonderful occasions—if his grandmother Settimia and her sister Pipinella did the cooking. "They were magnificent," Valenti says. "Always laughing, always really happy to be doing that Italian-grandma thing."

Settimia—"five feet two inches tall by five feet three inches wide"—is still his inspiration. Thanksgiving meals came naturally to her; after all, the hallmark of her everyday cooking was abundance "as if she were expecting, you know, the Green Bay Packers to appear at the door at any moment." On Thanksgiving mornings, she would go down into the basement, and soon Valenti would hear the telltale "bawk, bawk, bawk, bawk!" as she killed the holiday capons—roosters that grow "fat and yummy," Valenti says, after being neutered. But Settimia and Pipinella both died when Valenti was a teenager ("I lost about 60 pounds that year," he says), so he and his mother often spent Thanksgiving alone, "and were we going to do all that cooking for just the two of us?"

Valenti's mother often traveled for work. Before going she'd simply pack the larder with food, then she'd leave her son to fend for himself. For a teenager in a college town in the 1970s, the setup was heaven. "Everybody would converge at my house because there was no parental supervision," he says. Valenti, who still wears the long hair and wise and amused manner of a '70s wild child, fed the crowd.

Right after high school, Valenti apprenticed for a year at the best restaurant in Ithaca, L'Auberge du Cochon Rouge, where the strict and demanding Gallic chef, Étienne Merle, taught him to cook "big, rich, classic French food—very groovy," Valenti says. This inspired the luscious garlic-infused potato gratin on Valenti's Thanksgiving menu, plus a variation of the recipe in his brand-new cookbook, Tom Valenti's Soups, Stews and One-Pot Meals.

After Valenti left the Cochon Rouge, he worked as a personal chef on an estate in Westchester County, just north of New York City. His employer asked him to stock the wine cellar and encouraged him to seek out unusual ingredients and experiment with dishes—with only one restriction: Whenever Valenti cooked something, no matter how delicious, he could not repeat it for at least another 200 meals. But when his patrons divorced, "nobody sued for custody of the chef," he says, "so I kind of drifted off."

Apparently Valenti has a knack for drifting. His life story, as he tells it, is filled with chance encounters that turn, in almost Dickensian style, into great windfalls. After he had spent 15 months cooking at a Paris restaurant, Valenti serendipitously met chef Alfred Portale at Charles de Gaulle airport and wound up with a job as a sous-chef at Portale's Gotham Bar and Grill in Manhattan. Later, he ran into restaurateur Godfrey Polistina on Madison Avenue, and their casual conversation led to the opening of Ouest.

Between such moments of kismet, Valenti forged a "slow-cooked, falling-off-the-bone style," as he calls it, in such jewel-box Manhattan restaurants as Alison on Dominick Street, Cascabel and Butterfield 81. "I like to make food that's a little bit French and a little bit Italian grandma," he says, an approach that has attracted many regulars to Ouest, from director Steven Spielberg to writer Joan Didion. And this fall he opened a new Italian restaurant, 'Cesca. A few blocks south of Ouest, it pays more direct homage to Settimia.

Valenti's Thanksgiving dinner reflects this mix of nostalgic flavors and exquisite technique. The recipe for oyster-and-sausage stuffing goes back to the 18th century, when the oysters in New York Harbor were so huge, Valenti claims, that you needed only one to stuff a turkey. His updated version blends the meaty (sausage) and the briny (oysters) with an Italian influence (pine nuts). It's rich but, as he says, "it doesn't leave you feeling as if you've eaten a bowling ball."

Another feeling Valenti's menu doesn't leave you with is panic. Many of the dishes—from the creamy roasted butternut squash soup that's served with crispy chickpea fries tossed with sage and Parmesan to the fig tart with a pistachio crust—can be prepared almost entirely in advance and reheated if necessary. Even the caramel apple parfaits, layers of spice cake with sautéed apples and whipped cream, can be assembled in advance. "Thanksgiving is supposed to be a relaxed holiday. It's not designed to be a decathlon—throwing the shot put, running the mile," he says.

Over the years, Valenti and his wife, Abigail Wolcott, who owns a company that makes organic skin-care products, have assembled a group of close friends, many of them restaurant co-workers, who are as nurturing as the Italian family of his boyhood. In fact, Valenti says, with chefs for friends, it's almost like having an Italian grandmother again. "They're a very generous bunch. I spend a lot of time at meals saying, 'Please, no more.'" The experience is not all that different from visiting Settimia's house, where every day was like Thanksgiving. "She had that classic response when I walked through the door," he says. Then, imitating his role model: "'Tommy, you've got to eat something. You're too thin.'"

Kevin Conley, an editor and writer at the New Yorker, is the author of Stud: Adventures in Breeding, about the high-stakes world of Thoroughbred horses.