Heat the oil in a large pot over medium heat. Add onion and garlic, and cook until soft and fragrant.
Add vegetables – bell peppers, carrots, zucchini. Cook 5–7 minutes until slightly soft.
Add beans, lentils, tomatoes, and tomato paste. Stir well to mix everything together.
Season with chili powder, smoked paprika, cumin, cayenne (if using), salt, and pepper. Taste and adjust spices.
Add vegetable broth and bring to a boil. Reduce heat and simmer uncovered for 25–30 minutes, stirring occasionally, until lentils are tender.
Serve hot, garnished with fresh cilantro or parsley. Pair with rice, bread, or enjoy on its own.