In a large stockpot, heat the olive oil over medium-high heat, and sauté the onion, celery, and carrots for about 5 minutes or until they start to brown. Add the garlic and sauté for 1 minute more.
Remove the sausage from the casings, and crumble it into the pot. Cook, stirring well to break up sausage for about five minutes or until it is no longer pink.
Add the salt, pepper, oregano and crushed fennel seeds to pot and sauté for one minute.
Add the entire can of tomatoes and the chicken stock. Bring the soup to a boil. Add the chopped kale and lentils to the stockpot. Return the soup to a boil.
Reduce heat to medium-low, cover the pot, and let the soup simmer for 30 minutes or until lentils are tender..
Add extra salt, oregano, or fennel seeds to taste.
Notes
This recipe doubles nicely and freezes well.Store leftovers in the refrigerator for up to three days or in the freezer for up to three months.