After wandering through the huge open-air market of buniquilpan, in eastern Mexico, past stall after stall of chiles, cactus paddles, wild herbs, and what smells like a thousand toasted tortillas, we finally find the beans. Steve Sando runs his fingers through piles of them, hunting for discoveries, saying the names of the ones he knows. Dark red Sangre de Toro, bull’s blood. Glossy brown San Franciscano (“hints of chocolate and toffee,” he adds). Ojo de Cabra, the rare Eye of the Goat beans, with stripes and swirls of rich brown. Compared to the dull, plastic-bagged pintos and kidney beans in my neighborhood grocery store back home, these glisten like jewels.

Sando owns the California company Rancho Gordo, grower and seller of heirloom beans since 2002. Famous chefs across America (and some in Mexico) are among his most loyal customers. Thomas Keller, of The French Laundry, discovered Sando's beans a decade or so ago and has used them ever since. Rick Bayless of Frontera Grill, in Chicago, and Sean Brock, of Husk in South Carolina, order from him; so do Mexico City chefs Enrique Olvera, of Pujol, and Gerardo Vázquez Lupo, of Restaurante Nicos. The company sells many thousands of pounds a year through its two shops and mail-order business. Besides their taste and beauty, the beans are also unusually fresh: Unlike grocery-store beans, which can linger on shelves for several years, Rancho Gordo's beans are sold the year they’re harvested. They’re pricier than ordinary beans, but for an artisanal ingredient, they're affordable—a pound costs less than a small jar of fancy jam.

Although he's practically a patron saint of beans, Sando, 55, is anything but reverent. Sassy and gleeful is more his style. To customers who worry about the gas, he’ll say, “Gift with purchase,” and explain that more bean eating can help with that (he's serious; your digestive system adjusts). At his Napa shop, the walls are covered with steamy Mexican movie posters from the ‘40s and ‘50s. He has an unforgettable way of describing beans: “What's big and fat and creamy and makes everyone say ‘Wow’?” (Answer: ayocote blanco.)

With us in the market are Sando's Mexican partners, who've guided him to many a beany treasure. In 2008, while trying to source heirloom beans from Mexican farmers, Sando met Yunuen Carrillo Quiroz, an outgoing woman in her 30s, and steady, quiet Gabriel Cortes Garcia, her partner in life as well as business. Their company, named Xoxoc (sho-shoke), after xoconostle—sour cactus fruit, which they process several ways—was already set up for export to the United States. With Sando, they launched Rancho Gordo-Xoxoc Project, buy-ing from small-scale farmers and shipping their crops to California.

Steve Sando outside one of the hacienda’s kitchens; heirloom beans.

Often, the partners find new beans and meet farmers in markets like this. Today, though, they're seeing beans they already know. Also, it’s time for dinner. So we hoist ourselves into Gabriel's SUV and drive for an hour through open country, past opuntia cactus and scrubby yellow-flowering shrubs. Finally we bounce down a rutted road to his family home, the place everyone calls “the hacienda.”

A gorgeous, crumbling manor built in 1708, the hacienda has multiple court-yards, a chapel, and soaring ceilings. Most of the rooms have skylights rather than windows, which gives them an almost spiritual glow. The building was in fact a Jesuit monastery at one time, Gabriel explains. Mostly it was owned by wealthy silver-mining families, until the Mexican Revolution swept them from power. Now Guadalupe (Lupe) Romero Vidal, the daughter of the worker who took over the hacienda, lives there with her husband, Javier. Her best friend, Isabel (Chabela) Cortés García, mother of Gabriel and his brother, Antonio, moved in when the boys were small. About 10 acres remain of the original 106,000.

An entire wing is devoted to food: a dining room that looks like a museum exhibit of colonial life from the 1800s; a dimly lit pantry; and three kitchens, one dominated by an enormous bracero, a stove of brick and polished stone that is original to the hacienda. Lupe sets a clay olla—a bean pot—over a charcoal-fueled grate in the bracero and begins to simmer a batch of the rich, almost fudgy Moro beans that Sando loves.

Over the next two days, Lupe and Chabela fire up pot after pot of heirloom beans, each with its own character. The gorgeous red Sangre de Toro, for example, have skins so thin they seem to melt as you eat them. They’re a delight straight from the pot, but the ladies show us how many ways they can be served. Chabela adds a spoonful of requesón—ricotta cheese fried with green chile and epazote, an earthy, addictive herb—and they’re transformed into dinner. To another bowl, she adds more broth, oregano, and fried tortilla strips, and it's soup.

Mashed with chile paste, purple ayocote morado beans fill envelopes of fresh corn dough toasted on a giant griddle. Puréed with their own broth, cocoa-colored bayo chocolate beans make a sauce for dipping tortillas. Creamy white ayocote blanco go into salad. Most of the beans can be used for any of these dishes. “You can reinvent the same pot two or three times,” Sando says.

Lupe Romero Vidal with one of her bean pots.

As we watch the cooking, Quiroz, Sando, and Gabriel tell me the story of these beans. When trade protections disappeared in 2008 under NAFTA, cheap beans from the United States poured into Mexico, and heirloom farmers struggled to compete. Mexican grocery-store shoppers weren't interested in small lots of rare, indig-enous beans anyway. Many farmers pulled up their fields and migrated to the United States illegally, desperate for work. Their beans were in danger of disappearing too.

Sando decided to be a better neighbor. Rather than just buying beans once, or taking seeds across the border and growing them in Napa, he and Quiroz and Gabriel pay Mexican farmers to stay on their land and grow the beans they've raised for generations. One of the first people they worked with, Maria Bisma, used to grow her lovely gray rebosero beans all by herself. “She could only take as much to the market as she could carry on foot, 5 miles down the hill,” Sando recalls. When she joined the Rancho Gordo-Xoxoc Project, her grandson, who had been planning to cross the border to the United States, decided to stay and help her farm. “The solution to this whole thing is opportunity,” Sando says. “It’s not patronizing, it's not charity. It's validating what they do.” Eight years on, the project now works with 30 families all over Mexico. “Los que migren—those who migrate—now stay to work the fields,” says Gabriel. "They finally have money for what they know how to do. It's very good.”

We all sit down to dinner on the veranda at dusk, next to a courtyard of pink bougainvillea and butterflies. It's simple, incredibly good food built on corn and beans, the irreducible flavors of Mexico. As we eat, we talk—about family, the farmers, the beans they're still tracking down, and the satisfactions of the project. “We are creating a market,” says Quiroz. “I have the feeling of going down an ancient path and remembering as I walk. When the farmers plant, the past becomes alive again.” Sando agrees. But ultimately, he feels, it's neither sustain-ability nor respect for the past that gets people interested in heirloom beans. “The reason they buy these,” he says, “is because they taste great.”

Simple Pot-Cooked Beans

Frijoles de la Olla

Makes about 8 cups
45 minutes to 3 hours, depending on freshness of beans

Romero Vidal and Quiroz, with White Bean Salad

Cooked in this easiest possible way, beans have many possibilities: for eating as is, with toppings, as fillings, or in soups. To flavor them, Lupe Romero Vidal uses fresh avocado leaves, which have a delicately herbal taste but are unavailable in the United States; however, the pungent herb called epazote, carried by Latino markets and many grocery stores in the Southwest, makes a great flavoring too. Even without either, the recipe will still be good. You can certainly use olive oil instead of lard, but it's not as traditional (and the lard is delicious).

1 lb. dried beans, soaked overnight in water to cover by 2 in.*
1 whole Mexican boiling/grilling onion (cebolla) or ½ white onion, peeled
2 or 3 sprigs fresh epazote
1½ tbsp. Fresh Lard Seasoned with Herbs, Garlic, and Orange (link) or extra-virgin olive oil
About 2 tsp. medium-fine sea salt or kosher salt

Put beans in a 6- to 8-qt. pot and add enough water to cover by 2 in. (The pot should be large enough to allow plenty of air space over the beans and water, so steam can circulate.) Add onion. Bring to a boil, covered, over high heat.
Boil beans, uncovered, 10 minutes. Reduce heat to a bare simmer and cook, lid barely ajar, until beans are starting to get tender (from 20 minutes to 2 hours, depending on the age of the beans). Add epazote, lard or oil, and 2 tsp. salt.
Cook, lid barely ajar and adding enough hot water to keep beans covered by about 2 in., until beans are very tender but not broken, 15 minutes to 3 hours. Season to taste with salt.
Eat beans immediately or let cool in their broth. If eating right away, remove onion and epazote and ladle into warm bowls with some broth.
Soak the beans in water overnight to shave off cooking time. If you don't presoak, give the beans more time to cook—at least 30 minutes more (it varies depending on the freshness of the beans).

Fried Ricotta with Epazote and Green Chile

Makes about 2 cups
20 minutes

It's fine to use widely available moist, smooth ricotta rather than the artisanal curd type, but you'll need to cook it longer to dry it out, and your yield won't be as high.

1 tbsp. extra-virgin olive oil
½ cup minced white onion
2 cups ricotta, preferably the fresh, curd-style type, drained of excess liquid
1 tsp. medium-fine sea salt or kosher salt
One-third to ½ cup roughly chopped epazote leaves
1 to 2 tbsp. finely chopped green serrano, jalapeno, or arbol chile

In a large frying pan over medium-high heat, sauté onion in oil, stirring often, until translucent, about 3 minutes.
Add ricotta and fry, breaking up with a wooden spoon, until dryish, 6 to 10 minutes (the bottom of the pan will probably get a little brown). Stir in salt and remove from heat. Stir in epazote and chile.

Toasted Corn Pockets

Thicoyos

Makes about 15
About 2 hours

Toasted Corn Pockets; Gabriel fires up the bracero

Thicoyos can be filled with a range of ingredients, from mushrooms to roasted vegetables; Chabela Cortés García used beans mashed with chiles during my visit. (Tlacoyos means "snack" in Nahuatl, the language of the Aztecs, still spoken by more than a million indigenous Mexicans.) At the hacienda, they're topped with cheese and salsa and eaten as part of brunch. Ready-made fresh corn dough (masa) is worth seeking out for this; it has better flavor than corn flour and is easier to use.

3 dried guajillo chiles
5 dried arbol chiles
1½ cups Simple Pot-Cooked Beans, using ayocote morado (scarlet runner beans) or other dark red or black beans, with their broth
About 1 tsp. medium-fine sea salt or kosher salt
½ tsp. ground cumin
2 tbsp. Fresh Lard Seasoned with Herbs, Garlic, and Orange (link) or extra-virgin olive oil
1 lb. fresh corn dough for tortillas (masa para tortillas) or 8 oz. corn flour (masa harina)*
Oueso fresco,* for topping
Roasted Tomato and Arbol Chile Salsa or Fresh Green Chile and Tomatillo Salsa

Put guajillo and arbol chiles in a cast-iron skillet over low heat and toast, turning often, until lightly toasted and fragrant, 1 to 5 minutes depending on how brittle they are. Remove stems from chiles, cover with hot water, and let soak 15 to 20 minutes.
Meanwhile, lift beans from broth with a slotted spoon to a deep bowl, reserving broth. Add salt to beans. Using a pastry blender, potato masher, or machacadora* , mash beans into a coarse paste.
Drain chiles and put in a blender. Add cumin and Vs cup bean broth; blend, scraping down inside of blender a few times, until chiles are coarsely puréed and pourable. Add more broth if needed.
Pour chile puree into beans and mix thoroughly into a thick but creamy-looking paste; add more broth if needed to loosen. Season with salt to taste.
Put lard in a medium (not nonstick) fry-ing pan and melt over medium-low heat. Add chile-bean paste and fry, stirring, 5 minutes to blend flavors. Cool 15 minutes.
Meanwhile, if using corn flour, put it in a large bowl. Drizzle in 1⅓ cups hot water while kneading it into the flour with your fingers. Knead until dough is smooth, moist, and no longer sticks to your hands. If it feels dry, knead in a little more water; if it's sticky, work in a little more corn flour. Keep masa covered with a damp kitchen towel as you use it, since it dries out quickly.
Put a serving platter into a 200° oven to warm. Heat a large cast-iron skillet or griddle over medium-low heat.
Meanwhile, line both inner sides of a tortilla press with a piece of plastic, cut from a resealable bag, to be about the same diameter as the press. Pinch off a ball of masa (about 1¼ in. wide) and en-close it in your palm, squeezing your fingers over it to form it into a cigar shape. (It should just fit in your folded hand; if your fingers can't fit over it, remove some masa.) Shape cigar into a cylinder about 3½ in. long and tapered at the ends.
Set masa cylinder inside tortilla press and parallel to the handle. Use the press to flatten it until it's about ¼ in. thick. Rotate 180° and press again to flatten a little more.
Fill oval with about 1 tbsp. bean paste, spooning it down center. Using bottom plastic wrap to guide the soft masa so it doesn't stick to your fingers, bring both long sides of oval up to meet over filling; then fold them to one side over filling. Gently push ends of masa oval into points. With plastic over it, flatten the filled oval with your hands to about ¼ in. thick. Peel plastic off masa and put tlacoyo in skillet.
Repeat with remaining dough and filling, adding each tlacoyo as formed to skillet. Toast them until golden brown with some darker spots, about 2 minutes per side, then transfer to platter in oven to keep warm, covered with foil.
Top with queso fresco and salsa.
Buy this cool, moist, fresh corn dough (not to be confused with “masa preparada” or “masa para tamales,” which are coarser) at Latino markets. Or, use masa harina (pow-dered masa)for tortillas, reconstituted with water as directed in step 6. For tastier, prop-erly crumbly cheese, take the queso fresco out of its package a day beforehand, blot it, and let it dry out overnight (or even 2 nights), uncovered, on a plate in the refriger-ator. A machacadora is a Mexican-style bean masher; find one at ranchogordo.com or Latino markets.

Make ahead Freeze airtight up to 1 month.

Bean-Dipped Tortillas

Enfrijoladas

Makes 15 small or 12 large
1 hour

Bean-Dipped Tortillas with pickled chipotles

In many parts of Mexico, enfrijoladas are often just fresh tortillas dipped in a bean sauce and folded over. Lupe Romero Vidal and Chabela Cortes Garcia filled theirs with chorizo or leftover barbecued chicken and served them for brunch, but just about any leftover meat would be delicious—or even scrambled eggs. You'll have leftover bean sauce, which happens to make an excellent dip for tortilla chips.

¼ medium red onion, very thinly sliced
3 cups Simple Pot-Cooked Beans (recipe, using bayo chocolate* or cranberry beans), plus about 2 cups hot cooking broth
Medium-fine sea salt or kosher salt
1 cup lard* or vegetable oil
15 (5 in.) or 12 (6 in.) corn tortillas
1 lb. hard, spicy Spanish-style sausage, such as longaniza, chorizo, or linguica, thinly sliced; or soft Mexican-style chorizo squeezed from its casing; or shredded cooked chicken
Crema (Mexican-style cream)* or whisked sour cream, for topping
Crumbled queso fresco* or shredded Monterey Jack cheese, for topping Pickled chipotle chiles (recipe) or store-bought pickled jalapeños or escabeche (mixed pickle)

Put onion in a bowl and cover with cold water. Set aside.
Pour beans into a blender and add salt to taste, plus enough bean broth to cover by about 1 in. Blend until very smooth.
Preheat oven to 200° and set a serving platter inside to warm. Line a rimmed baking sheet with paper towels. Put lard in a medium (not nonstick) frying pan over medium-high heat.
When lard is melted and hot but not quite smoking, slip a tortilla into it and fry until slightly crisp around edges but still flexible. Turn over once (clasp between 2 “nested” spoons to avoid tearing), 30 seconds to 1 minute total. Transfer to paper towels to drain. Repeat with remaining tortillas, layering between paper towels as needed. Put filled pan of tortillas in oven to keep warm.
Pour out all but 1 tbsp. lard from tortilla-frying pan. Add chorizo and fry over medium-high heat, stirring occasionally, until crisp around the edges (if using Mexican chorizo, fry until broken up and well browned), 8 to 10 minutes. Transfer to a bowl.
Reduce heat to medium-low, pour bean sauce into pan, and heat, stirring, until steaming; then reduce heat to low. Sauce should be no thicker than heavy cream; add more hot bean broth or water if necessary to thin it.
Using spoons again to grip tortillas, dip one tortilla at a time into bean sauce to thoroughly coat both sides. Lay on warmed serving platter and cover half of one side with a few pieces or a spoon-ful of chorizo. Fold over. Repeat with remaining tortillas, bean sauce, and chorizo. Drizzle with a little more sauce, then top with onions, queso fresco, and crema. Serve with pickled chiles.
Find bayo chocolate beans at ranchogordo. con:. For the lard, use the soft, brown, fresh Mexican-style lard from the deli counter at Latino markets, or any other fresh (non-hydrogenated) lard; vegetable oil will work, but it won't taste the same. Find cre-ma and queso fresco at Latino markets too. Queso fresco is tastier and crumblier if removed from its package, blotted dry, and allowed to sit, uncovered, 1 to 2 days in the refrigerator.