Brown the Italian sausage. Heat the olive oil in a large Dutch oven (or heavy-bottomed soup pot) over medium heat. Add the Italian sausage and cook, breaking it up with a wooden spoon as it cooks. Continue to crumble the meat. Once the meat is fully browned, drain off any excess grease and transfer it to a plate.
Add the aromatics. To the empty pot, add the diced onion and sauté for about 4-5 minutes until softened (add butter if not enough fat remains in the pot). Stir in garlic and cook for another minute, or until fragrant.
Add the seasonings. Mix in the Italian seasoning, basil, paprika, crushed red pepper flakes, salt, pepper, and chopped sundried tomatoes. Let everything cook together for another minute to wake up the spices.
Making the soup base. Pour in the chicken broth and return the sausage to the pot. Bring the pot to a gentle boil, then reduce the heat and let it simmer for about 10 minutes so the flavors can come together.
Make it creamy. Reduce the heat to low and slowly stir in the heavy cream. Add the grated Parmesan a handful at a time, stirring continuously until it’s completely melted into the broth. The soup should be smooth, creamy, velvety.
Add the tortellini. Add the refrigerated tortellini and cook according to the package directions, usually about 4 to 6 minutes, until they’re tender and floating to the top.
Finish with spinach. Stir in the butter and fresh spinach. The spinach will wilt in just a minute or two. Give everything one final stir, taste, and add salt until everything tastes “bright” and flavorful, stirring well in between additions.
Serve and enjoy. Ladle the soup into bowls and top with Parmesan cheese, chopped fresh basil, and plenty of cracked black pepper. Serve it warm with crusty garlic bread, or a simple green salad for the ultimate cozy dinner.
Notes
Slow cooker: Brown the sausage, onion, and garlic first, then transfer everything except the cream, Parmesan, spinach, and tortellini to the slow cooker. Cook on low for 5-6 hours, or on high for 2 ½-3 hours. During the last 30 minutes, stir in the cream, Parmesan, and tortellini. Stir in the spinach once the cooking time is up, stirring until it wilts. Taste and adjust for salt, then serve and enjoy!Fresh or frozen tortellini? You can use either fresh (refrigerated) or frozen tortellini, but refrigerated is our top pick. Fresh tortellini cooks a bit faster and more consistently, so if you have to pick between the two, we recommend fresh over frozen. That being said, frozen works perfectly fine! Just check the center to ensure they are cooked all the way through.Storing: Transfer leftover soup to an airtight container, and store in the refrigerator for up to 3 days. Soup will thicken after storing, as the tortellini absorbs more liquid. Adding more broth or cream during reheating is helpful.Reheating: Reheat gently over medium-low heat on the stove, adding a splash of chicken broth or heavy cream if needed to loosen the broth.Can I freeze this soup? Because of the heavy cream and tortellini, we don’t recommend freezing this soup. Tortellini can become very soft and mushy after re-freezing and re-thawing, and the cream can separate.Kale or chard: If you want to swap out the spinach for kale or chard, that’s totally fine! Kale especially gives a lovely zuppa toscana vibe.