Making mole sauce, with its complex mix of sweet and spicy, is hard work. Eating it,in all its variations, is great fun.

On a recent two-week excursion through the state of Oaxaca, traveling with noted New York-based restaurateur and cookbook author Zarela Martinez (her Zarela is widely considered to be the best Mexican restaurant in Manhattan), I discovered a graceful and sophisticated colonial city, visited a craggy coffee-growing village in the mountains, sweltered in a steamy-hot Indian seaside town, and met a host of wonderful people. I also ate one great meal after another, and discovered the truth about mole.

Oaxaca is the land of mole -- and one of the first things I learned about it here is that, the usual Americanized Mexican restaurant cliche notwithstanding, there’s a whole lot more to mole (pronounced “moe-lay”) than just chicken in chocolate sauce. The word, in fact, describes a whole genre of sauces--there are said to be seven traditional moles in all--which might include, in various combinations, such ingredients as tomatoes, roasted chiles, squash seeds, sesame seeds, bread and many different kinds of nuts, herbs, spices and fruits. Chocolate is indeed an important part of many moles -- but not every one. And though many moles are served with chicken, that’s only one of the many things these sauces can enhance.

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Our trip began in Mexico City, where we hired a car and driver to take us to Oaxaca--the city of that name, which is the capital of the state. Along the way, we passed through high deserts, lofty mountain ranges, dense tropical forests. The lush hills were splashed with late-summer light, illuminated patches of orderly cornfields, groves of pines and palms, mangoes and papayas.

The weather was warm and sunny but punctuated with brief showers that intensified the sharp smell of the earth. In the rugged mountain village of Huautla, where coffee is grown, we stopped to look at a wall of splendid roaring waterfalls. Huautla became famous in certain circles in the 1960s, not for its coffee but for its psychedelic mushrooms--and, as we stood there, one local, recognizing us as Americans, stopped to inform us that he thought Bill Clinton would do a better job if he were to sample some of them.

Arriving in Oaxaca, we settled into Hotel Las Golondrinas, a small, immaculate, moderately priced hotel built around a richly landscaped garden. It was dinner time, and nearby, we discovered a charming no-frills taco restaurant called El Meson, where we sampled soft tacos filled with verdolaga (purslane) in a creamy sauce, served with mounds of sweet grilled green onions. After dinner we took a stroll through town and ate fresh coconut and “burnt milk” ice cream on the plaza in front of the church of La Soledad.

Oaxaca is a colonial city, artistic and lively but serene. We found simple pleasures all over town. The ornate churches of La Soledad and Santo Domingo are dazzling with their intricate baroque adornments, often leafed in gold. They make a stunning contrast with the plain but bright stucco houses that surround them, painted in pink, azure blue, orange and yellow. One morning in Santo Domingo, I heard a tiny woman in a black mantilla filling the church with a sweet, resounding song that mourned the death of her husband.

On another day, we visited the Museo Rufino Tamayo, which displays not works by the noted artist, but his own impressive collection of pre-Columbian sculpture. We had drinks in the famed El Presidente Hotel (now owned by Stouffer), a 400-year-old former convent whose walls are still covered with pale peeling religious frescoes. (Italo Calvino describes the hotel and its paintings vividly in his long short story “Under the Jaguar Sun.”) We had coffee and toasted rolls, again and again, at one of the outdoor cafes under the graceful portals surrounding the busy tree-lined zocalo , or main square.

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And we haunted the city’s markets. The principal Indian market, Central de Abastos, really bustles--especially on Saturdays, when merchants and farmers from the surrounding countryside come to Oaxaca to sell their wares. Here, for breakfast in one of many little restaurants set up for shoppers and merchants, I had my first mole of the trip, an authentic version of the kind of mole I’d experienced in watered-down versions in the United States. This was an aromatic, piquant, slightly sweet mole negro , or black mole (made with chocolate, nuts, chiles, assorted herbs and spices and possibly a pureed banana), poured over a chicken breast with rice. It gave me plenty of energy for hours of market browsing.

Except for the fact that there is no longer a section set aside for the bartering of slaves, the marketplaces of today in Mexico apparently look much as they have for many centuries. (There is a model of a 14th-Century Aztec market at the National Museum of Anthropology in Mexico City.) Merchants still display their wares on rugs or straw mats on the ground. And though some of the particulars may have changed, the heady variety of products sold seems almost medieval. The scents of hanging meat, freshly made hot tortillas, braids of garlic, bundles of onions, piles of peppers, baskets of exotic herbs and spices, bouquets of tuberoses and more greeted us.

As we walked down one aisle lined with baskets of chiles, their pungency assaulted us so boldly that our lungs started burning and we had to turn away coughing. Elsewhere, woven baskets stood next to modern plastic and tin cooking utensils; there were live turkeys with their talons bound, platters of tiny red fried grasshoppers, smoked worms (a local delicacy) threaded on strings, yellow squash blossoms, baby avocados (called “butter of the poor”), pyramids of recycled Nescafe jars, ears of corn and corn husks for tamales, lovely crumbly-fresh feta-like cheeses. . . .

Special mole booths sold packaged pre-made versions of mole negro and mole rojo , or colorado (a dense brownish-red mole made with, among other things, chiles, tomatoes, sesame seeds, cinnamon seeds, cinnamon and a little chocolate). Either at these booths or elsewhere in the market, one could also find all the ingredients necessary for the other moles-- amarillo (yellow mole, a stew of vegetables and small dumplings in a sauce of amarillo chiles, spices and herbs, thickened with masa harina , or prepared tortilla flour); verde (green, usually made with pumpkin seeds, the herbs epazote and hoja santa , parsley, tomatillos and green chiles); chichilo (beef in a black sauce flavored with toasted avocado leaves and charred dried chiles); coloradito (“little red,” a mild, thick, reddish-orange mole made with amarillo and ancho chiles), and manchamanteles (“tablecloth stainer,” made with dried fruit and nuts).

As I soon found out, though, mole may come in seven basic types--but there are many more variations on the theme than that, especially in the countryside.

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One day, we headed out to Teotitlan del Valle, about 15 miles from Oaxaca. This is one of Mexico’s most famous weaving villages, and the oldest town in the Valley of Oaxaca--predating even the pyramids of Monte Alban, built around 750 BC by the indigenous Zapotec Indians. Our destination was a well-known Zapotecan restaurant, Tiamanalli de Abigail Mendoza Ruiz--but we also hoped to meet a famous local cook and rug-weaver named Zoyla Mendoza. We found her at her family store, and she joined us for lunch at the restaurant. We started with complimentary mescal and guacamole, then had mild squash-blossom soup accompanied by small fried tacos filled with cheese and more squash blossoms.

Then came the moles, two of them. One was a kind of mole colorado --sharp, savory, robust, brick-red, not at all sweet--served over a crisp chicken breast with black beans. The other, served with chicken breast and white beans, was a very smooth, understated cream-colored sauce, flavored with pumpkin seeds and various herbs. Both were complex, delicious, forthright but subtle--a revelation to me.

Though served in a restaurant, these moles were really “homemade,” since they were prepared in the traditional at-home way, with virtually all the ingredients painstakingly ground and amalgamated by hand with a metate , or grinding stone, and mano , or stone rolling pin.

To show us how painstaking the creation of an authentic mole could be, Zoyla invited us to her house to help her and some friends make chocolate for a mole negro from scratch. When we arrived, we found her in the garden with several small, dignified Zapotec women, their hair woven with bright silk ribbons into long braids. Turkeys, chickens and guinea hens pecked the ground nearby, amid sunset-orange poinciana trees and pink bougainvillea blossoms. On the ground, on a straw mat, was a large metate.

A small fire was lit, and a comal --a flat, round, unglazed clay dish used to roast everything from beans to grains to chiles to tortillas--was set over it. Onto the comal went heaps of cocoa beans, which one of the women pushed back and forth patiently until they were done. When they had cooled, we all pitched in to shell them. Bits broken off long cinnamon sticks were mixed in with the beans. Then, a tiny bucket filled with hot embers was placed under the metate. Onto the metate went the cocoa beans and cinnamon, and for an hour and a half we took turns slowly grinding them into a molten mass on the heated stone. The last step was mixing in sugar.

Chocolate, of course, is only one ingredient of mole negro. If we’d been making the entire sauce, the next step would have been to roast or fry sesame seeds, peanuts, almonds, more cinnamon, tortillas, dried bread, cloves, allspice, thyme, oregano and raisins--along with a variety of chiles and their seeds. All these ingredients but the chocolate and chiles would then be mixed into a paste with chicken broth and fried in lard. Finally, the chocolate and chiles would be added and the sauce would be ready.

Not all Oaxacans grind and roast and fry all the ingredients for their moles, of course. Some cooks blend various elements of the sauce at home and then send the mixture to a mill to be ground professionally. Others use an electric blender. Improvising on the mole theme is a popular local pastime.

The next day, our last in Teotitlan, Zoyla invited us to a lunchtime goat feast. To tide us over in the morning, though, she served us a breakfast mole called mole de castilla, made with fresh Oaxacan oregano, roasted pumpkin seeds, cumin and dried bread, among other things. It reminded us of nothing so much as an Italian bread soup.

The goat, meanwhile, was stewing in a large pot buried in a hole in the ground, with embers underneath, anise-flavored avocado leaves and guajillo chile sauce on top and heated rocks over that. When the feast was ready, we ate the pungent, spicy meat with large, pale baked tortillas, beer and mescal.

Traveling on through the state of Oaxaca, we came into the stifling stillness of the Isthmus of Tehuantepec, the narrowest part of Mexico. Here, in the city of Juchitan, we encountered another way of serving of mole -- enchiladas doused in mole negro sauce. Tortillas were dipped in the dark grainy sauce, wrapped around chicken and sprinkled with thinly sliced white onions and crumbled queso fresco. The dish was a brown-and-white still life, complex and well balanced, with the cheese, onions and tortillas cutting the sweetness of the chocolaty sauce.

Back in Mexico City, on our way home, we couldn’t resist trying one last mole . We dined at the handsome, well-regarded Fonda el Refugio, where we sampled a perfectly acceptable mole negro, said to contain 25 ingredients. Compared to the moles we’d been eating in Oaxaca, it tasted hesitant and subdued.

GUIDEBOOK

On the Mole Trail

Getting there: Mexicana offers numerous daily connecting flights from Los Angeles to Oaxaca, most taking between 9 and 14 hours (some are overnight); fares begin at $435 round trip. It is also possible to drive to Oaxaca from Mexico City, a journey of about 10 hours. All major rental car agencies have facilities in the Mexican capital, and, with an advance request, most can arrange for drivers.

Where to stay: Hotel Las Golondrinas, Tinoco y Palacios 411, Oaxaca; from the U.S. telephone 011-52-951-421-26 or 011-52-951-687-26 for reservations. Rates: about $28-$33 for two. Stouffer Presidente Oaxaca (formerly El Presidente Hotel), Calle Cinco de Mayo 300; tel. 011-52-951-606-11, fax 011-52-951-607-32 or (800) 468-3571 for reservations. Rates: about $120-$200 for two.

Where to eat: In Oaxaca: Restaurant El Meson, Hidalgo 805 (no telephone), about $20 for two. La Catedral, Garcia Vigil y Morelos 105; local tel. 632-85, about $40 for two. Mi Casita (Cocina de Antequera), Hidalgo 612, tel. 692-56, about $40 for two.

In Teotitlan del Valle: Restaurant Tiamanalli de Abigail Mendoza Ruiz, Juarez 39, tel. 202-55 (open for lunch only, 1 to 5 p.m.), about $40 for two.

In Mexico City: Fonda el Refugio, Liverpool 166, tel. 52-858-23, about $65 for two.