Our longtime, very Parisian friend, Bernard Collet, a photographer and my Emily Post guide to French customs, says that what always reminds him that I'm American is my habit of inviting strangers home for dinner. Pre-party jitters often have me worrying that this jumble of old friends and new won't work. But it does. Always. Perhaps it's the magic of the changing year or maybe it's the spell of Paris that makes us feel like members of the family we all wish we were born into.

Ever since I was just out of college, I've wanted to live in Paris. I didn't want to just move to Paris, I wanted to be Parisian and live my American dream of a Parisian life: to be able to tie my scarf perfectly; to gracefully negotiate cobblestone streets in heels; and to be the person who always has champagne in the fridge, ready for à la minute frivolity. I wanted to be as close to French as a girl from Brooklyn could be. And if my New Year's Eve party were the sole measure of my Gallic makeover, I'd score high—it's a swell party. More than that, it's a tradition that we treasure.

It began decades ago when I received a postcard from a friend who'd been transferred to Paris for work. The picture on the card was of the gloriously gilded and grand Pont Alexandre III, the most ornate bridge over the Seine, lamplights glowing and the river calm beneath it. The message said something like, “We greeted the New Year here, drinking champagne and tossing our empty oyster shells into the water.”

To me, a graduate student living in New York with an uncertain future, the image of Paris at midnight, champagne, oysters, and the Seine was enchanting and more fairy tale than Cinderella. From then on, when my husband, Michael, and I would toast on December 31, we'd say, "Next year in Paris!" It took a long time, but when I started working with pastry chef Pierre Hermé in Paris and writing more about France and its food, it began to seem practical. Finally, in the winter of 1997, we signed the lease on our first Paris apartment, walked to the corner, went into the Café Bonaparte, ordered champagne, and toasted, "This year in Paris!"

After all these years, there are party regulars, of course, and they're a marvelous and mixed group: French and American, expats and pats, several food and wine people, artists, writers, fashion people, designers, one mathematician, and one son, Joshua. Most years our guests span five decades and every year it feels both spontaneous and rooted, a party repeated annually for the pleasure of being together in Paris.

The start of the evening plays out like this: I encourage people to go into the living room and nibble. They ignore me and stay in the kitchen, crowded, cramped, and content to sip champagne shoulder to shoulder and to serially munch gougères, cheese puffs from Burgundy, which have become my signature. It's all I can do to shoo people out and get the meal going.

While we don't actually chuck our shells into the Seine, we do kick off dinner with oysters. They're a constant at French end-of-year celebrations, and starting just before Christmas, wood crates of Fines de Claire, Spéciales, and Gillardeau with their trademark G somehow stamped in the shells turn up in open-air markets and even the corner 8 à Huit, France's version of 7-Eleven. And I'll put out jars of homemade, luxurious smoked-and-fresh salmon rillettes for the non—oyster eaters among us.

The main course is always the tough choice for me—once I went with all appetizers and les français thought I'd made un pique-nique. For the past few years, fish stew's been my go-to plat de résistance, as the French so heroically call the main course. My most recent version of the stew is a touch Asian—yuzu kosho, lemongrass, chile, and lime tilt any dish eastward. I was flattered when my French friends wrote a day later and said they loved my nouvelle bouillabaisse.

Although I might make last-minute changes to the party, I hold some parts of the meal to be immutable—having lots of dessert is one of them. There are always macarons, an annual gift from my friend Pierre Hermé, and I make something, too, this year three kinds of cookies and a marquise au chocolat, a royal dessert, similar to a chocolate mousse, from the 17th or 18th century.

Because our celebration inevitably starts late, there's a witching-hour scramble to get to the bridge and welcome the New Year. With luck, we finish the cheese course before midnight and march bridgeward, setting out with champagne bottles and glasses, pouring for people as we go.

Our bridge is the Pont des Arts. It's not as dolled-up as the Alexandre, but it's my favorite, a wooden pedestrian crossing with the Louvre to one side and, on the other, the Institute of France, a domed building that many consider architecturally perfect. From its crest you can see most of the Eiffel Tower; turn around and you catch the Tour Saint Jacques and the lights of Notre Dame.

One year, a friend brought a Balthazar, a 12-liter behemoth of bubbly, to dinner. She claims the bottle was a thank-you for something I did, but I can't remember ever doing anything that deserved something so spectacular. We opened the bottle at the start of the evening—it took 45 minutes to remove the handmade cork!—and when it was time to go to the bridge took the remains with us. To say that the sight of a massive bottle of great champagne making its way through the streets caused a stir is an understatement. Midnight arrived, we toasted, we embraced, we wished everyone well; and when we returned, there were people following us Pied Piper style. As our son said, “I never want to go anywhere without a Balthazar in my arms—you meet the best people!”

If he wanted to, he could still travel with the Balthazar. We saved the empty bottle: It is signed by everyone who shared that evening with us and sits on a shelf in our dining room. Like the postcard that inspired the tradition, it's a reminder that sometimes the best planning is just to make sure you find yourself every year in the city you love best, surrounded by the people you love the most.

Greenspan began her career in cookbooks as a baker. As such, her holiday table often serves as a mini showcase of her current favorite desserts. A few below are adapted from her latest—and 12th—cookbook, Dorie's Cookies.