1. Heat 1 tablespoon olive oil in a large pot over medium heat and brown the Italian sausage until cooked through. Remove and set aside.
2. In the same pot, add 2 tablespoons olive oil and sauté leek (or onion), shallot (or celery), carrots (if using), and garlic, seasoning with salt and pepper. Cook until vegetables are softened, about 4-5 minutes.
3. Deglaze the pot with white wine or broth, stirring for a few minutes to lift the browned bits.
4. Add crushed tomatoes and stock. Stir in herbs such as herbs de Provence, Italian seasoning, or oregano if desired. Bring to a simmer, then reduce heat and cook partially covered for 20-30 minutes.
5. Add gnocchi directly to the soup and cook until tender (about 2-10 minutes depending on the gnocchi).
6. Stir in heavy cream, return the browned sausage to the pot, and add spinach. Cook briefly until the spinach wilts.
7. Season with additional salt, pepper, and red pepper flakes as preferred.
8. Serve hot, garnished with shaved or grated Parmesan cheese. Fresh crusty bread or garlic bread pairs well.