Sort through the brown lentils to remove any small pebbles. Rinse in cold water, drain and reserve.
Heat oil in a Dutch oven over medium heat. Add onion, fennel, carrots, and celery; cook, stirring often for 5 minutes. Add sausage, breaking up with a fork. Cook, stirring often, until no longer pink, about 5 minutes.
In a small dish add the tomato paste and water, whisk together until smooth then add to the soup pot. Pour in the chicken broth, add the reserved lentils, Italian seasoning, cumin and bay leaves.
Bring soup to a boil. Cover and reduce heat to low. Simmer until lentils are tender, about 20-30 minutes. Add salt and pepper to taste.
Remove from heat, discard bay leaves and ladle into soup bowls. Sprinkle each serving with chopped parsley
Notes
An easy way to sort the lentils is to spread them out on a sheet pan. Discard anything that is not a lentil.
When breaking up the sausage leave small chunks of for flavor and interest.
This is a hearty, thick soup. Add additional chicken broth for a thinner soup.