1. Cook the bacon in a large stockpot over medium-high heat until it begins to crisp. Remove it with a slotted spoon and set aside to drain on paper towels.

2. Add the onion, garlic, carrots, and celery to the bacon fat in the pot; sauté, stirring occasionally, 10 minutes. Stir in the jalapeños and cook 5 minutes more. Stir in the cumin and oregano.

3. Rinse and drain the black beans and add to the stockpot. Cover with 3½ quarts chicken broth. Simmer uncovered until the beans are very tender and beginning to fall apart, about 2 hours. Thin with additional broth if the mixture seems to be getting too thick.

4. Stir in the lime juice, and sherry, and reserved bacon. Season to taste with salt and pepper. Just before serving, swirl in the cilantro. Serve piping hot in bowls garnished with a dollop of sour cream.