Black Bean Chili

1 pound dried black beans, picked over, rinsed, soaked in water to cover for 1 hour, then drained
1 large onion, chopped
4 tablespoons minced onion
3 tablespoons extra virgin olive oil
1 tablespoon ground cumin
7 cups water
1-2 chipotle chilies in adobo, seeded if desired, chopped
1 28-oz can pureed tomatoes (or puree a can of whole tomatoes)
1 cup chicken or vegetable broth
1 red bell pepper, chopped
1 teaspoon Mexican oregano
1/3 cup chopped cilantro
juice of one lime

freshly chopped avocado for serving at the table

Sate onions and garlic in the olive oil in a large pot over medium heat. When onions are soft, add cumin and cook another minute, stirring. Add drained beans and the water. Increase heat and bring to a boil. When boiling, reduce heat to a simmer and cook 1 hour or until beans are tender. Add chipotle chilies, broth, bell pepper, oregano, and salt to taste. Simmer 30 minutes more. Puree half the soup if desired, either in blender, food processor, or hand-held blender. Stir in coriander and lime jice and simmer 5 more minutes. Serve hot, topped with chopped avocado.