Let me tell you about Puebla, a city obsessed with a sauce. You think Naples is nuts about tomato sauce? That Paris is passionate about beurre blanc? You haven’t seen anything until you’ve seen how they carry on about mole poblano in Puebla. Ever since the exotic chile-and-chocolate sauce was invented there in the seventeenth century, the city has been the epicenter of mole mania.

This summer a friend and I spent a week in the city and witnessed the phenomenon for ourselves. Every other restaurant had a sign in the window advertising chicken in mole (“mo-lay”). The chef of a popular hotel dining room told us he sells a thousand orders a month. At a neighborhood food market, alongside the freshly plucked chickens and buckets of flowers, I saw stack after stack of small plastic tubs of mole made by the wives and mothers of vendors; brimming bowls were set out so you could stick your finger in and taste. The local yellow pages list seven mole manufacturers, and a mole cookoff is held every June. Everyone has an opinion about whether you should use peanuts or almonds and if it’s better to toast or fry the chiles. Quirky family recipes are treasured heirlooms: One woman told me that her mother always included six crumbled-up vanilla cookies; another said her mother insisted on two charred corn tortillas, for a smoky flavor.

What’s so great about mole? It’s hard to explain because, to Americans, the crucial combination of chiles and chocolate sounds bizarre. Mole is basically an Aztec chile sauce accented with Spanish spices and ground nuts. The name, from the Nahuatl molli, means a “concoction” or “mixture.” The Spanish word poblano means “Puebla-style.” Generally, when it comes to mole, people either love it or hate it. Me, I loved it the first time I tasted it, more than thirty years ago on a trip to Monterrey. The aromas of coriander and cinnamon and toasted sesame seeds wafted up from the plate. The first mouthful was tropical—plantains, raisins, and almonds—followed by a tingle of warmth from the chiles. Underneath it all was the seductive sweetness of the chocolate. Spicy, sweet, and sultry, mole seemed to me like all of Mexico condensed into one dish. Ever since then I’ve been on a quest to taste as many versions as I can. In Puebla, I thought, I might even find the perfect mole poblano.

My companion on this journey was my friend and fellow food fanatic Gini Garcia, of San Antonio. This past July the two of us met at the Mexico City airport to complete the final leg of our journey to Puebla, about eighty miles southeast. After a 25-minute plane ride, we took a cab into town and checked into the Holiday Inn, a modern hotel in a historic building with an austere and semicavernous, castlelike lobby.

VIPS, a bustling chain restaurant, bookstore, and drugstore, wasn’t the most auspicious place to start sampling mole, but it was just down the street and we were famished. Surprise, surprise: VIPS’s mole wasn’t bad. The sauce was lighter in color than some, brick-red rather than brown, and very peanutty. We approved. We finished our dinner and took a stroll around the zócalo—the big, immaculately swept town square—to enjoy the scene and the weather, a perfect 70 degrees. Businesspeople with briefcases walked briskly by and young mothers bought balloons for their children. Puebla is a beautiful and dignified city, filled with Spanish Colonial buildings covered in colorful tiles, many arranged to form bold stripes and zigzags. It is also an old city, dating from 1531, and a big one, with some 2.5 million people in the metropolitan area. Above the palms and other tall trees sheltering the zócalo we could see the towers of the nearby cathedral.

The next day we met Mónica Mastretta, a local caterer and cooking teacher who works with tour groups, for lunch at the casual, open-air dining room of the rather grand Hotel Royalty. She said its mole was among the best in the city, and she was right. Dark and chocolaty, it had a strong allspice flavor and a delayed chile kick. The chef, a descendant of the hotel’s founder and now a co-owner himself, told us that the original recipe was his grandmother’s and the hotel has used it, almost unchanged, for 45 years. Could I have already found my perfect mole? Maybe. It is so popular that the Royalty has a nice sideline selling it in jars to go.

After lunch the irrepressible Mónica took us on a whirlwind culinary tour of downtown Puebla. She was wearing high heels and we were in sandals, but it was all we could do to keep up. We turned down several streets and finally came to a tiny cafe with bright plaid tablecloths. Although we hadn’t intended to eat again, we found ourselves sitting down at Pepe Grillo, ordering enchiladas in mole. Rather light in color, a little granular, with lots of sesame flavor, the sauce had an appealing homemade quality. Afterward, Mónica dragged us a few blocks farther to Fonda de Santa Clara, a pleasant if touristy spot that is the city’s most famous mole outpost. Gini and I were way too full to sample another drop of mole, but that night we went back for dinner. Santa Clara’s mole lost points with us because it was served lukewarm, but otherwise it was good—rich, chocolaty, not too sweet.

We had breakfast the next morning with Ana Elena Martínez, also a caterer and tour guide, who filled us in on more of the city’s locally famous foods. Agreeing to meet her later for lunch, Gini and I took off for her first recommendation, Nevados Hermilo, a humble cafe with Formica-topped tables, to try the odd little cocktails called nevados, served on the rocks in small glasses. Our dour waitress wouldn’t reveal the recipe, but they seemed to be made with rompope (rum-spiked Mexican eggnog) and various liqueurs and flavorings. “Hey, breakfast of champions,” said Gini as we toasted each other with a couple of Pingüinos (kicked up a notch with Kahlúa) at ten in the morning. Feeling no pain, we walked over to the local candy street, Seis Oriente (the section of the street just east of Cinco de Mayo), where we found a dozen or so shops selling gaudy sweets like squishy camotes (made from yams) displayed in cases buzzing with deliriously happy bees. Then we raced six blocks over to La Pequeñita, one of four tidy permanent food stands by a parking garage, to try molotes, freshly deep-fried and irresistible turnovers made of corn tortillas that had been folded over and crimped around various fillings. I avoided the meat fillings but felt that the requesón, a ricotta-type cheese, and slivers of jalapeño were safe.

By now it was time to hook up with Ana Elena again for two lunches. The first was at Mi Ciudad, a rollicking restaurant with terrace seating, fine mole (mild, medium-sweet, strong taste of peanuts and cinnamon), and a whole range of local specialties, including chanclas (stuffed sandwiches that tasted like Mexican sloppy joes). No sooner had we finished than we headed out for lunch number two (you thought it was a breeze being a food writer, didn’t you?), at La Tecla, a chichi place with a subdued brown-and-gray color scheme and a modern fusion menu. Its far-out combo of very sweet, caramel-colored mole sauce over fettuccine, liberally sprinkled with Parmesan, was strange but it grew on me. Dinner that night was at La Cueva del Zorro, a fifteen-minute cab ride from downtown, where Gini and I knocked back some tequila and shared a molcajete, a Mexican lava-stone mortar, filled with sizzling strips of arrachera (the local name for fajita meat) plus grilled nopalitos (cactus pads), onion, and chorizo and melted white cheese. It was fantastic.

So far we hadn’t done much sightseeing except for walking around downtown, so the next morning we strolled a few blocks to La Capilla del Rosario, an absolutely glorious rococo chapel that is part of the Iglesia de Santo Domingo. Standing in its splendid, gold-leaf-encrusted interior was like basking in a sunbeam. Afterward we took some time to shop at El Parián, an engaging downtown outdoor market with gifts, clothing, home accessories, and lots of the brightly painted Talavera pottery that Puebla has been famous for since colonial times. (I personally counted 15,896,741 pieces on display.) When we had maxed out our credit cards, there was just enough time to engage in another strange local food ritual, so we walked over to the Plazuela de los Sapos, or Toad Plaza, across from which is a little storefront named La Pasita. This is the place where everyone from construction workers to CEOs stands in line to order a pasita—raisin liqueur served in a small, slender glass containing a toothpick-impaled raisin and cube of salty white cheese. We slugged down our pasitas and grabbed a cab for a last-minute lunch.

Long story short, the first place we intended to try was closed; the second seemingly did not exist. So, in desperation, we turned to our cab driver, a talkative, clean-cut kid who had been telling us all about his favorite place to eat tacos árabes—spit-roasted pork and onions wrapped in pita bread, a local specialty. “Drive,” we said. In fifteen minutes we were at his favorite taco spot, a bare-bones joint named Israel out in the boonies, tearing into meltingly tender wood-roasted pork, five salsas and other condiments, and a dish of melted cheese mixed with tidbits of bacon and beef. I would never tell my mother I had eaten at a place like this, but what an adventure.

On Sunday Gini took off to spend a couple of days in Veracruz, so I headed out alone to the weekend flea market at the nearby Plazuela de los Sapos, which was filled with dusty books on subjects like Tu Personalidad, brass candlesticks, rusty door hinges, peculiar paintings, and tattered comics featuring the mysterious character Fantomas. That afternoon Ana Elena drove me over to the Mercado Venustiano Carranza, a big, basic food market away from downtown (at Cuatro Poniente and Trece Sur), specifically to have a cemita, another local specialty. Cemita is the name of a soft, crisp-crusted sesame-seed bun and the sandwiches made with it. People here are as crazy about them as Americans are about hamburgers, and the Carranza market is the place to have them. You get a choice of meats (or none, if you prefer), plus avocado, onion, two kinds of white cheese, and a bit of chipotle chile, all drizzled with olive oil, for a bargain price of $2.50.

The next day I ate at Fonda de Santa Teresita, a popular spot far from the center of town, with walls painted royal blue and papaya orange. For a change of pace, I ordered a chile en nogada, a batter-fried poblano stuffed with fruit and covered with a sweet sauce made of fresh, just-picked walnuts and cream (this dish too was invented in Puebla, though not as long ago as mole poblano). And because I couldn’t help myself, I asked the waiter to give me just a taste of the kitchen’s mole. It had a lot of sesame and plantain but was light on the chocolate. Even so, I liked it. In fact, I hadn’t tasted even one mole that I didn’t like. In the late afternoon I tried a spot called Fonda la Mexicana, a pin-neat cafe down the street from the cathedral. The owner was ready to close, but when I begged pitifully, he brought me a piece of bread and a saucer of mole: thinnish, chile-hot, very chocolaty. I could have lapped it up.

Gini and I hadn’t intended to save the best part of the trip for last, but that’s the way it worked out, and I’m glad it did. On our final day in the city, we decided it was high time to visit the Ex-Convento de Santa Rosa, the former convent where mole poblano was created more than three hundred years ago. What a great place. To my mind, it’s the best entertainment value in the city. Downstairs is a small contemporary crafts shop selling, among other things, indigenous pottery that is exactly the color of my favorite mole—the Hotel Royalty’s. Upstairs, surrounding the ancient building’s central courtyard, are rooms filled with exhibits of zany papier-mâché skeletons and devils and the like. The museum guide grinned when we stopped in front of a clay mole pot measuring some four feet in diameter. “Americans usually say, ‘Hey, a Mexican Jacuzzi,’ ” he said. But the former convent’s centerpiece, located downstairs, is the huge, sumptuously tiled kitchen where, sometime in the 1680’s, a Dominican nun named Sister Andrea de la Asunción invented mole. As the story goes, the local bishop wanted to impress a visiting viceroy and, knowing that Sister Andrea was quite a cook, he asked her to make something original. She thought about it on a Sunday (maybe she said a little prayer), then went into the kitchen the next day and made a special sauce. As luck would have it, a large, chestnut-fattened turkey had just been killed, and she cooked the bird to complete the main course. The dish was an instant hit, other area convents requested the recipe, and within a few years it had spread all over the city, becoming quite the thing to serve at trendy dinner parties.

We left elated, regretting only that we couldn’t get a copy of the original recipe; like most chefs, Sister Andrea seems not to have measured anything or written it down. Three early versions do exist, however, and they are remarkably similar to the recipes that you can find in Puebla today. I think the good sister would be tickled to know that the mole madness she kindled hasn’t died down yet.

Getting there: To get to Puebla, you must fly to Mexico City (nonstop flights from Dallas–Fort Worth on Aeromexico, American, and Delta; from Houston on Aeromexico, Continental, and Delta; and from San Antonio on Mexicana and United). From Mexico City you can fly to Puebla via Aeromexico or Mexicana. Our cab into town cost $14 (it is generally safe to take taxis in Puebla).

Where to stay: Holiday Inn, Dos Ote. 211, 011-52-222-223-6600, fax 222-242-1176; holidayinnpuebla.com.mx, hotel@holidayinnpuebla.com.mx. From $72 for a single or double room to $280 for a suite.

Where to eat and drink: Fonda de Santa Clara, Tres Pte. 920; entrées $5–$12. Fonda de Santa Teresita, Veintinueve Sur 3512, at Treinta y siete Pte.; entrées $4–$12. Fonda la Mexicana, Diez y Seis de Septiembre 706; entrées $5–$9; closes at 7 p.m. Hotel Royalty, Portal Hidalgo 8, across from the zócalo; entrées $8–$15. Israel Tacos Orientales, Diagonal Defensores de la República 702; entrées $1–$5; no credit cards. La Cueva del Zorro, Chapulco 28; entrées $5–$10. La Pasita, Cinco Ote. 602; $1.50 for a pasita. La Pequeñita, Cinco Pte. 113; $1 for a molote. La Tecla, Av. Juárez 1909; entrées $5–$10. Mi Ciudad, Juárez 2507; entrées $6–$12. Nevados Hermilo, Cuatro Norte at Dos Ote.; $2.50 for a nevado. Pepe Grillo, Diez y Seis de Septiembre 703; entrées $1–$6; closed Monday; no credit cards. VIPS, Dos Ote. 201; entrées $5–$10.

What to do: Ex-Convento de Santa Rosa, Catorce Pte. 305; admission $1 (free Tuesday); closed Monday.

Travel Tips

Positive ID: The Mexican government requires that U.S. citizens take either their passport or both their birth certificate (the original or a certified copy) and a photo ID, such as a driver’s license.

Ouch: At least a month before you leave, consult your physician or a hospital travel clinic about recommended shots or medicines for diseases like hepatitis A, typhoid, and malaria.