1Soak beans overnight. Drain and rinse, discarding liquid.
2Combine oil, mustard seeds, chili powder, cumin and cardamom in a 5 to 6 quart dutch oven. Place over high heat and stir until spices sizzle, about 30 seconds. Add onions, mushrooms, tomatillos and 1/4 cup water. Cover and cook, stirring occasionally, until vegetables are juicy, 5 to 7 minutes. Uncover and stir often until the juices evaporate and the vegetables are lightly browned, 10 to 15 minutes. Add broth, tomato paste and chipotle with sauce; mix well.
3Add the beans to the dutch oven, cover and simmer over low heat, stirring occasionally, about 4 hours, or until the beans are soft. Add tabasco sauce to taste.
4To serve, ladle soup into bowls, garnish each serving with cheese, sour cream and cilantro.