1. Heat 1/4 cup water or oil (if using) in large skillet over medium heat. Add onion, and sauté 3 minutes. Stir in garlic, bell pepper, and mushrooms, and cook 3 minutes, adding up to 2 Tbs. water if mixture starts to stick to skillet. Add lentils, carrot, celery, chili powder, cumin, paprika, oregano, bay leaf, and cayenne (if using), and sauté 1 minute, stirring constantly. Stir in broth, and bring to a boil. Lower heat to medium-low, cover, and simmer 30 minutes, stirring occasionally. If mixture starts to dry out, add up to 1/4 cup water or broth.

2. Remove from heat, and drain off excess liquid (a bit of liquid is fine). Remove bay leaf, and stir in tomato paste and lime juice. Transfer to food processor or blender, and pulse a few times, or until texture is crumbly (do not purée). Serve warm.