First, heat the olive oil over medium heat n a large heavy duty dutch oven. Then add the chopped onions and red bell pepper. Saute the vegetables for 8 minutes or until soft and lightly browned, stirring occasionally.
Stir in the garlic and chili powder, and cook for 1 minute.
Next, add the lentils, tomatoes, bay leaf and vegetable or chicken stock. Season with salt and ground black pepper to taste. Bring the pot to a boil, and then lower the heat to medium-low. Allow the chili to simmer, partially covered for 30 minutes or until the lentils are tender. Remove from the heat and discard the bay leaf.
Transfer 3 cups of the cooked chili into a food processor and process until pureed. Then add the pureed chili back into the pot and stir to combine. Add salt and pepper to taste, if needed.
Stirl in the chopped cilantro and serve hot.
