There are regional differences in what is added to beans cooked this way, but each recipe will guide you-or should.
Yield: Makes 7 to 8 Cups, Without The Broth
1 pound (450g) dried beans (bayos, flor de mayo, or pinto )
½ medium white onion, roughly sliced
1 tablespoon lard (optional)
Salt to taste
Pick over the beans carefully to get rid of any little stones or bits of chaff. Cover them in a bowl with cold water and skim off any flotsam, shriveled beans, or anything else you might have missed while picking them over.
Drain the beans and put them into a heavy pot with the onion and lard, if using. Cover well with hot water; it should come about 4 inches above the level of the beans. Cover the pot and set over high heat until it comes to a boil. Lower heat to medium and continue cooking until the skins become tender. Add the salt and continue cooking until the beans are soft but not falling apart. This Will take anywhere from 2 to 3 hours, depending on the age and quality of the beans.
Keep some hot water on hand to top off the water if it is getting low-never add cold water.
Frijoles Negros De Olla
Makes A Scant 7 cups, Without The Broth
Follow the method for Frijoles de Olla, using 1 pound (450g) black beans and adding a sprig of epazote when you add the salt. Allow for a longer cooking time.
Frijoles De Olla Oaxaquenos
Follow the Frijoles de Olla recipe, adding ½ small head of garlic, cut horizontally, and a large sprig of epazote from the beginning.