Brown the sausage in a large pot over medium heat, breaking it up into pieces as it cooks.
While the sausage is cooking, prepare your vegetables: wash, peel and slice the carrots, slice the celery, dice the onion, and mince the garlic. Once the sausage is cooked, add the vegetables to the pot and continue to sauté until the onions are soft and transparent (about 5 min).
Measure out the lentils and pick through them to make sure there are no stones. Add them to the pot along with the cayenne, cumin, smoked paprika, oregano, and chicken broth.
Place a lid on the pot, turn the heat up to medium-high, and allow it to come up to a boil. Once it reaches a boil, reduce the heat to low and let simmer for 30 minutes or until the lentils are tender. Add more water if it gets too dry.
Stir in the frozen spinach and cook for about 15 minutes more. Serve with a thick slice of crusty bread!