In a large pot or Dutch oven, heat olive oil over medium heat. Add chopped onion, carrots, and celery. Sauté for 5-7 minutes until softened.
- Add minced garlic, cumin, turmeric, cinnamon (if using), and dried thyme. Cook for another 1-2 minutes until fragrant.
- Add ground turkey, cooking and breaking it up until browned and cooked through, about 5-7 minutes. Season with salt and pepper.
- Pour in the broth, diced tomatoes (with juices), lentils, and bay leaf. Stir to combine and bring to a simmer.
- Reduce heat to low, cover, and simmer for 30-40 minutes until lentils are tender. Add additional broth or water if soup becomes too thick.
- Once lentils are cooked, remove the bay leaf. Adjust seasoning with salt, pepper, or spices, and add fresh lemon juice if desired.
- Serve hot, garnished with fresh parsley or cilantro.