Start by heating the oil in a large stockpot over medium. Sauté the onions, celery, and carrots for a few minutes, then add in the garlic and cook for another minute or two. Continue cooking for about 5 minutes, then add in the tomatoes and cook for another 5 minutes, or until the veggies are softened.
Mix in the cumin, paprika, and cayenne, then add the rinsed lentils, vegetable broth, and bay leaves. Give everything a good stir until it’s well combined.
Bring the soup to a low boil and reduce the heat to simmer until the lentils are tender and creamy. When the lentils are soft, season your soup with salt and pepper to taste, and adjust the other seasonings to your preferences. Happy eating!