On Christmas Eve, star San Francisco chef Michael Mina and his family have a sleepover at the Westin St. Francis hotel, site of his eponymous restaurant, before heading home for a magnificent Christmas dinner.

Eight-year-old Sammy Mina holds the rib bone steady as his dad, chef Michael Mina, carves perfect slices of slow-roasted prime rib for Christmas dinner. No chef could ask for a better apprentice. Sammy, who has been cooking since the age of three, eagerly joins his father at San Francisco's Westin St. Francis hotel every Saturday, meticulously wiping the plate rims just as any sous-chef would. Sometimes four-year-old Anthony tags along with his older brother, but, as Sammy says, "he's the wild one," as likely to end up under a customer's table as to help with the cooking.

This is a family that feels right at home in hotels. Mina, who opened the spectacular Michael Mina restaurant at the St. Francis last year, even met his wife, Diane Tirado, in a hotel, San Francisco's Clift, where she ran tea service and he was pastry chef. (He wooed her with homemade mocha-almond-fudge ice cream, her favorite flavor.) This year the Mina family decided to have their traditional Christmas Eve dinner at the St. Francis, spend the night in a suite upstairs, and wake up on Christmas morning to waffles in bed. Afterward, they'd head home for Christmas dinner itself.

Mina has always loved Christmas. He was raised in a Coptic Christian family that emigrated from Egypt to rural Washington State when he was a year old. Though his mother baked her own flat breads and made ful, a velvety fava bean puree, Mina wanted to eat only American foods like hamburgers and pizza. "I thought, how could I bring friends home for falafel?" he says.

At age 15, Mina took a job at a local bistro and, enraptured, started cooking 50 hours a week, partly for school credit. His parents, who expected to raise a doctor or a lawyer, finally threw up their hands and sent him to the Culinary Institute of America, in Hyde Park, New York.

In 1991, Mina and his mentor, George Morrone, opened the seafood restaurant Aqua in San Francisco. Its popularity soared beyond expectation, with luxurious dishes like lobster potpie and osetra caviar parfait. When Morrone left Aqua three years later, Mina, just 24 years old, became the restaurant's executive chef. He started experimenting with variations on a single ingredient, a concept that is now fully realized at Michael Mina. One of his signature "trios," as Mina calls them, features three seared and three seviche scallops paired with different sauces: one sauce with Meyer lemon beurre blanc, Meyer lemon vinaigrette and caviar; another with corn custard, corn salad and black truffles; and the third with lobster, tomato butter and tomato water.

Mina is now in charge of five restaurants, all in hotels, including Las Vegas's Michael Mina Bellagio, which opened in July. His sole business partner is tennis star Andre Agassi, a regular customer who became a friend. But Mina makes all the major decisions. He hired the acclaimed designer Barbara Barry to decorate the high-ceilinged space in the flagship restaurant at the St. Francis in a luxe palette of beiges, pearly grays and pale blues that matches the opalescent tones of the huge Thai oyster-shell chargers on the tables. Tall windows look out onto Geary Street and Union Square, a center for holiday shopping that gets decked out with lights and bows at Christmas.

During their Christmas Eve dinner at the hotel this year, Diane and the boys settle in at the restaurant waiting for Mina to bring out his cioppino, a San Francisco seafood stew with Dungeness crab, shrimp and clams that his Italian mother-in-law, Judith Tirado, used to include in her holiday celebrations as a nod to the traditional Italian Christmas Eve fish feast. For dessert, Mina bakes his version of Key lime pie—a lemon curd tart with a cookie-crumb crust flavored with cinnamon and nuts.

The next morning the kids wake up to a special breakfast of crunchy cornmeal-and-ricotta waffles and bacon. Later everyone piles into the car to go home and begin the festivities in earnest. Mina's Christmas dinner always starts with French onion soup topped with melted truffle-pecorino cheese. Then, alongside the simple, delicious prime rib roast that Sammy helped carve are whole Yukon Gold potatoes that have been roasted inside a blanket of salt—the salt helps distribute heat, so the potatoes cook evenly and stay moist—and served with a trio of flavored butters: scallion, mustard and horseradish. For dessert, Mina brings out banana tartes Tatin, crackly with caramelized sugar.

When it's time to eat, Sammy proudly shows off his dining room skills: He carries each plate to the table, carefully sets it down and turns it slightly, just as a professional waiter would.

Restaurant Michael Mina, 335 Powell St., San Francisco; 415-397-9222.

Patricia Unterman, restaurant critic for the San Francisco Examiner, is the author of the San Francisco Food Lover's Guide.