· 1 pound dried pinto beans, rinsed (see Note)· 1/2 large white onion· 1 tablespoon kosher or sea salt, plus more as needed· 4 dried Colorado chiles (also known as California or New Mexico chiles), or guajillo chiles, stemmed and seeded· 1 to 2 whole canned chipotles in adobo, plus 1 tablespoon adobo sauce· 3 tablespoons vegetable oil or lard· 8 ounces asadero, quesadilla, Monterey Jack or Oaxaca cheese, grated (about 2 cups)· 1 ounce crumbled Cotija (about 1/4 cup), for garnish
Step 1Place pinto beans in a large pot and cover with 14 cups water. Add the onion and set over high heat. Once it comes to a boil, reduce the heat to medium, skim off any foam that may have risen to the top, partly cover with a lid and cook for 1 hour.Step 2Remove the lid, stir in salt, partly cover with the lid, and cook for another 15 to 30 more minutes, until beans are completely cooked through and tender and the liquid is tinted from the pinto beans.Step 3Meanwhile, place the dried chiles in a small saucepan, cover with water and set over high heat. Once the liquid comes to a boil, reduce heat to medium and simmer, uncovered, for 10 minutes, until chiles have rehydrated, softened and plumped up.Step 4Remove the lid on the beans, and, using a slotted spoon or a pair of tongs, discard the onion.Step 5Working in batches if needed, add the cooked beans along with 2 cups of their cooking liquid, the dried chiles, the chipotle chiles and the adobo sauce to a blender or food processor, and pulse until the mixture forms a coarse purée.Step 6Heat the oil in a large, heavy casserole or sauté pan set over medium. Once hot but not smoking, carefully add the bean purée, as it will strongly sizzle and splatter. Stir well, incorporating the hot oil into the bean mixture. Cook for 10 to 12 minutes, stirring often and scraping the bottom and sides of the pan as the refried beans continuously attempt to create a crust, until the mixture thickens.Step 7Stir in the grated cheese, and continue to cook for another 10 to 15 minutes, stirring frequently and scraping the bottom and the sides, until the mixture thickens to a thick purée that holds its shape, and a clear trail can be traced in the bottom of the pan.Step 8When ready to serve, scrape into a bowl and garnish with the crumbled Cotija. Beans will last up to 5 days in the refrigerator. Reheat them in a saucepan or skillet with a couple tablespoons of water over medium and mash as they warm up, since they have a tendency to thicken once chilled.