Sauté the aromatics: Heat olive oil in a large pot over medium heat. Add the onions, garlic, celery, and carrots. Sauté until soft, about 5 minutes.
Add the spices: Stir in turmeric, cumin, coriander, ginger, cinnamon, black pepper, and paprika. Cook for another minute until fragrant.
Simmer the soup: Add lentils, chickpeas, broth, and the bay leaf. Bring to a boil, then reduce heat and simmer for 40-45 minutes, or until the lentils and chickpeas are tender.
Finish with herbs: Stir in parsley and cilantro, then add lemon juice for a bright, fresh finish.
Adjust seasoning: Taste and add more salt or spices if needed. If using cooked rice, stir it in at the end.