In a large pot over medium heat, add the Italian sausage, breaking it up as it cooks. Sauté until browned, about 5-7 minutes. Drain excess fat if necessary.
Add the diced onion to the pot and continue to cook for about 3-4 minutes until the onion is softened. Stir in the minced garlic and cook for an additional minute until fragrant.
Pour in the chicken broth and bring the mixture to a gentle simmer.
Add the tortellini and Italian seasoning to the pot. Cook according to package instructions, usually about 3-5 minutes.
Once the tortellini is tender, stir in the fresh spinach and heavy cream. Let it simmer for another 2-3 minutes until the spinach wilts, and the soup is heated through.
Season with salt and pepper to taste.
Serve hot, topped with grated Parmesan cheese and a sprinkle of fresh parsley.
Notes
Adjust the spiciness of the sausage based on preference.