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, a home cook in Hidalgo, Mexico, 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 pound dried beans, soaked overnight in water to cover by 2 in.*
1 whole Mexican boiling/grilling onion (cebolla) or 1/2 white onion, peeled
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).
Recipe time: 45 minutes to 3 hours, depending on freshness of beans.