Ingredients

    * 3½ cups dried black beans
    * 2 tablespoons corn oil or other vegetable oil
    * 1 medium onion, diced
    * 2 cloves garlic, minced
    * 1 chipotle chile
    * ¼ ancho chile
    * 1 tablespoon cumin
    * 1 tablespoon paprika
    * 1 tablespoon dried oregano
    * ¾ tablespoon sea salt
    * 1/8 teaspoon cayenne pepper
    * 2 tablespoons wine vinegar (red or white)
    * 1½ cups diced tomatoes
    * 1½ cups tomato puree
    * 4 cups water
    * sour cream for garnish

Preparation

   1. Place beans in a large pot and cover with enough water to cover by 2 inches, and 
allow to soak overnight. Drain beans and cover again with fresh water. Bring to boil, 
reduce heat, and simmer for 2 hours.
   2. Heat the corn oil in a stockpot or other very large pot over medium-high heat. 
Add the onions and sauté until tender, about 3 minutes. Add garlic, chipotle and ancho 
chiles, cumin, paprika, oregano, salt, cayenne, and vinegar, and sauté for 5 to 10 
minutes.
   3. Add tomatoes, tomato puree, and 4 cups water. Bring to a boil, then reduce heat 
and simmer for 10 minutes. Add the beans with their juice. Simmer for 1 hour. Serve 
with or without sour cream.