In a large soup pot, heat olive oil over medium heat. Add onion and red bell pepper; saute the vegetables for 8 minutes or until onion is soft and lightly browned.
Stir in garlic and chili powder; cook for 1 minute.
Add lentils, tomatoes, bay leaf and vegetable stock. Bring to a boil, lower the heat to medium-low and simmer partially covered for 30-40 minutes or until lentils are tender. Remove from heat and discard the bay leaf.
Transfer 3 cups of cooked chili into a food processor and process until pureed; add the pureed chili back into the remaining hili and stir to combine. Adjust salt and pepper as needed. ( I did not puree any chili )