Brown sausage in a large pot over high heat with a pinch of fennel, once sausage is browned remove from pot and set aside.
Add vegetables to fat remaining in pot, and cook until tender, then deglaze pot with sherry.
Add lentils, chicken stock, Italian herbs, and tomato paste.
Simmer until lentils are tender (Between 20-40 minutes, depending on lentils)
Taste for seasoning, and serve