In a large pot, heat the olive oil over medium heat. Add the chopped onion, diced carrots, and diced celery. Sauté for about 5 minutes, or until the vegetables are softened
Add the minced garlic, ground cumin, ground coriander, smoked paprika, cayenne pepper, and turmeric powder to the pot. Sauté for another 1-2 minutes until the spices are fragrant.
Add the rinsed lentils, bay leaf, vegetable or chicken broth, and diced tomatoes (with their juice) to the pot. Stir to combine.
Bring the soup to a boil, then reduce the heat to low. Cover the pot and let the soup simmer for about 20-25 minutes or until the lentils are tender.
Remove and discard the bay leaf.
Stir in the chopped kale or spinach and let it wilt in the hot soup.
Add the lemon juice and season the soup with salt and pepper to taste. Adjust the seasoning and spiciness according to your preference.
Ladle into serving bowls. Garnish each bowl with chopped fresh parsley or cilantro for a burst of freshness and color.
Serve the soup hot with crusty bread or your favorite side.