1. Heat olive oil in a large, non-stick pot over medium-high heat. Add onions, green epper, celery, and garlic. Cook and tir until vegetables begin to soften, about 5 minutes
2. Add chili powder, cumin, oregano, coriander, red pepper flakes, and cinnamon. Mix well and cook for 1 more minute. Add undrained tomatoes, beans, tomato sauce, broth, brown sugar, salt and pepper. Bring mixture to a boil. Reduce heat to low and simmer, covered, for 20 minutes. Remove from heat and stir in cilantro (if using). Serve hot.
3. Optional: garnish with light sour cream and grated cheese.