My dear friend Hahna adapted this recipe from The Joy of Cooking, and she offers notes to make sure your soup turns out as well as hers always does.
• 1 pound dried black beans, rinsed and picked over
• 3 tablespoons olive oil
• 1 cup chopped celery, including the leaves
• 1⁄2 cup chopped onion
• 1⁄2 cup chopped carrots (If not in the mood for chopping, I'll leave these a bit large and run them through the food processor at the end.)
• 4 garlic cloves, minced
• 1 teaspoon sugar
• 1⁄2 teaspoon cumin
• 1⁄4 teaspoon dried thyme
• pinch of ground red pepper
• 1 ham hock
• 1 bay leaf
• salt and pepper
Drain beans, reserving the liquid. Add enough water to the reserved liquid to make 8.5 cups. Pour the olive oil in a large soup pot over medium heat. Add celery, onion, and carrots and cook, stirring, until onion is translucent. Add and cook garlic, sugar, cumin thyme, and red pepper, stirring, until fragrant, about one minute.
Stir in the reserved bean soaking liquid and the beans and add ham hock and bay leaf. Bring to a boil, reduce the heat and simmer, covered, two and a half to three hours, until the beans are tender.
Discard bones and bay leaf, if using. (I'll "pick" the ham hock, add the meat to the soup after processing, and save the fat and skin to make kale or something delicious.)
Puree half of the soup in a food processor or blender and stir back into the pot. Stir in salt and pepper to taste.
You can garnish the soup with chopped scallions or salsa, if you like.