What does legendary chef Jacques Pépin do when he needs a break? He escapes to the bustling beach town of Playa del Carmen, Mexico, to watch the waves, drink chilled rosé and transform the best local ingredients into simple recipes that showcase his elegant French technique.

When Jacques Pépin gets ready to cook a meal at his vacation home in Playa del Carmen, Mexico, he's as laid-back as the other residents of this beach town, less than an hour south of Cancún. Strolling the aisles of the market, contemplating a mound of plump avocados or sniffing a leaf of the herb epazote, he has no shopping list in hand, no classic recipes in mind. "It is harder if you try to make a specific dish," he says in the French accent he hasn't lost in nearly 50 years of living in the United States. The best plan in Playa del Carmen, where he and his wife, Gloria, bought an apartment two years ago, is to avoid planning altogether. "I go to the market, I see what comes knocking, and then I buy," he says.

Today, a glossy pile of poblano chiles catches his attention. "Last week when Jean-Claude was in town, we cooked these with fish, it was incredible," he says, piling them into his basket. Jean-Claude Szurdak, Jacques's best friend and fellow chef, and Jean-Claude's wife, Geneviève, often join the Pépins on vacation. "I like to add the chiles to a bed of diced jicama to simmer fish, just a little, so the fish gets tender. Then I serve the fish and vegetables on a very thick sauce, really a puree, of black beans and cilantro. Ever since I started coming to Mexico, I use a lot more cilantro," he says, grabbing a large leafy bunch.

Having a kitchen in which he can prepare dishes like these is one of the reasons the Pépins bought a vacation home overlooking the Caribbean Sea in booming Playa del Carmen, which locals claim is the fastest-growing town in the world. "It was love at first sight," Jacques says of the town. "We adored the exciting atmosphere. It's a fantastic walking town, bustling with shops and restaurants, most of them lining the main street, Quinta Avenida, or Fifth Avenue."

The Pépins spend at least two months a year in Playa (they rent out the apartment to vacationers when they're away). Given Jacques's intense work schedule, the time he spends in Playa is nearly his only chance to paint (his naturalistic watercolors, acrylics and drawings line the living room walls), play (especially boules near the beach and snorkeling around the region's famed coral reefs), rest (napping with his poodle, Paco, on the terrace), and cook for himself and for friends, just for fun. "It is the friendliness of the people that brings us back, along with the food, of course," he says.

Jacques's vacation meals in the terra-cotta-tiled kitchen are neither strictly French nor Mexican, but a delicious amalgam of the two. Along with the poblano-spiked fish, he might prepare a garlic and pasilla-chile soup mellowed with crème fraîche. Or he might make braised chicken legs and chayote with a sauce of mulato chiles and diced chorizo. The inspiration for this chicken dish, Jacques tells me, was a beautiful basket of taut-skinned, pale green, squashlike chayote at the market. The chayote reminded him of a dish he'd made before with squab; because he couldn't find squab in Playa he substituted chicken and added chorizo for a stronger, more robust flavor that evokes squab's rich gaminess.

The idea to serve this dish alongside ruddy-red achiote rice flavored with the chicken drippings came straight from his childhood memories. "You know, you're walking in woods and you smell something and all of a sudden you're five years old?" he asks as we leave the market and climb into his red Volkswagen Beetle. "That's what that rice dish is like for me. It's like what my mother would do when I was a kid. When she made a chicken, she scooped out the fat and used that to sauté the onions for a pilaf. It is called riz au gras, rice with fat. So I thought of that. But I added some of the spice achiote, which they use in Mexico and in Puerto Rico, which reminds me of my wife, because she is half Puerto Rican. So it's all these associations that build a dish. You start with one thing, it reminds you of something else, and so on."

Jacques wants to prepare his fish with poblanos and jicama for dinner, so we drive out to the beach, hoping to find a fisherman who got lucky. But when we arrive, the scene is unpromising: a dozen or so small wooden boats bob on the water, tied up and empty. "Maybe the water is too choppy, so they didn't want to go out," Jacques muses, squinting into the distance to make sure there isn't just one small boat on the horizon with our meal in tow.

"Usually you find someone, but I guess not today," he says, disappointed. The week before, he and Jean-Claude had scored a 16-pound grouper for which, after some pro forma haggling, they paid about $25. "It seemed cheap to us, but the fisherman made the sign of the cross, he was so happy with the price."

Instead, we decide to stick to the unplanned, Mexican-vacation approach, and figure out what to eat for dinner while we're having lunch. It's almost 1 p.m., time to pick up Gloria at the apartment, a three-minute walk away.

When we arrive, Gloria, elegant and tanned, is perched on the sofa facing the Caribbean Sea, feeding Paco shards of her chicharrones (pork rinds). "Paco loves crunchy things," she coos, caressing the poodle's black curling fur, "and I love chicharrones—it's my Puerto Rican heritage—so we're both happy."

"When Paco is happy, I am too," Jacques jokes, kissing his much-adored pooch squarely on the nose.

Gloria pours three glasses of chilled French rosé for us, and takes a sip. "I like this wine, where did you find it?" she asks Jacques, fending off Paco, who is intent on getting at the bowl of chicharrones.

"Sam's Club, with Jean-Claude," Jacques says. "Last week, we saw ibérico ham there! You can't get that in the States, it's really hard to import there. And it was so cheap, I think no one else here knew what it was."

At Dr. Taco, Jacques and Gloria's favorite taco stand, we eat squid tacos and something called a shrimp burger, made with melted Manchego cheese and served on a bun, then mull over the problem of where to find fish for dinner. We guess that if the fishermen on the beach didn't go out in the rough waters, neither did the fishermen who supply the market. We talk about this for a while, leisurely ordering yet another taco, as the afternoon wanes and Paco falls asleep on Jacques's lap.

Gloria peers at her watch and sighs. It is nearly time to go back to the apartment for cocktail hour. At dusk, Gloria tells me, monkeys regularly come out to play in the trees just below their terrace, a sight we definitely shouldn't miss. Plus, it really was getting too late to start thinking about cooking.

We finish our beers. Jacques and Gloria decide that we'll have dinner at a local restaurant they like, La Bamba Jarocha, post-monkeys. And we all agree to contemplate finding fish—or whatever else comes knocking—tomorrow. After all, that's what nice long vacations are for.

Melissa Clark's 17 cookbooks include Chef, Interrupted: Delicious Chefs' Recipes That You Can Actually Make at Home and East of Paris, with David Bouley.