In a large soup pot, heat olive oil over medium-high heat. Add onions and cook, stirring occasionally, until soft, about 3 minutes. Add garlic, bell pepper, and tomatoes. Cover and cook 5 minutes. Add kasha, wine, and broth. Stir to blend. Cook, covered, 5 minutes. Add kidney beans, chili powder, cumin, cilantro, and bay leaf. Cover and cook over medium-low heat for 40 minutes.
Add mushrooms. Add salt to taste. Simmer for 5 minutes. Discard bay leaf and cilantro.
Serve hot. If desired, serve with sour cream, chopped scallions, and grated cheese on the side.