These black beans are one of the simplest and most ubiquitous dishes in Mexican culture. They can be served with a sprinkle of queso fresco and salsa, or fresh serrano chiles, cilantro and a squeeze of lime with warm tortillas. Also a delicious side dish for most any main course, Mexican or not.
Pour the black beans onto a rimmed baking sheet and sort through them to remove any damaged or broken beans and any pebbles or other foreign objects.
Transfer the beans to a large heavy pot (like a Dutch oven) and cover them with cold water to rinse. Drain the beans and add water to cover the beans by about 2 inches. Let them soak overnight. The beans will rehydrate.
Drain the black beans and rinse again until the water is clear. Transfer the black beans back to the dutch oven.
Add the quarter of onion and two garlic cloves. Pour the 8 cups of water over the beans and bring to a boil. Cover the pot and simmer for 1 1/2 hours to 3 hours (it really depends on the beans and how old they are as to how long they will need to cook) until they are tender.
Use a sharp knife to make a slit along the side of the serrano pepper so steam can escape.
Remove the lid and add the epazote or bay leaves (if using) and serrano. Continue to cook with the lid off, stirring occasionally for 20-30 minutes or until the beans are soft. Season with salt and lard or olive oil if using.
MEXICAN BEANS IN AN INSTANT POT:
Add the beans, onion and garlic to the Instant Pot with 7 cups of water. Cook for 30 minutes on the Bean setting with the valve closed.
Quick release the beans. Test a bean to verify its tender Add the serrano pepper and epazote or bay leaves(if using) and continue pressure cooking the Mexican beans for 5-10 minutes (depending on how ).
Season with salt and lard or oil and cook for 5 additional minutes with the lid off on sauté. Stir occasionally.
FOR THICKER, CREAMIER CONSISTENCY BEANS:
For thicker beans, scoop out 1-2 ladles of cooked beans (1/2 to 1 cup) and a little broth and mash them with a potato masher or blend them in a blender or food processor until smooth. Add the mashed beans back to the pot and stir to combine.
Serve with desired garnishes or as a side dish to a larger meal.