In a large stock pot over medium heat, cook the ground sausage.
Once the sausage has started to brown, add the 3/4 cup onion and 1/2 cup poblano pepper (if using). Let cook for 1 minute. Add the 1 cup of celery.
Add 6 cups of broth, 1 cup of carrots/parsnips, 15-ounce can of diced tomatoes and spices. (2 teaspoons cumin, 1 teaspoon cinnamon, 1 teaspoon paprika, 1/2 teaspoon sumac, 1/4 teaspoon cloves, 1/2 teaspoon red pepper flakes).
Add 1 cup of lentils and 1 tablespoon of lemon zest.
Bring soup to a boil and boil for 5 minutes. Reduce heat to medium and simmer for 20 minutes or until lentils are soft. If you like a bit firmer of a lentil, simmer for less time. You will want to check at the 10 minute mark to see how firm the lentils are.
Enjoy with a nice crusty bread or toasted English muffin!