Heat the olive oil in a large pot or Dutch oven over medium heat. Add the Italian sausage and cook, breaking it up with a spoon, until browned. Drain off any excess grease.
Add the chopped onion to the pot and cook until softened, about 5 minutes. Add the minced garlic and cook for 1 minute more until fragrant.
Pour in the chicken broth and add the diced tomatoes (with their juice), Italian seasoning, salt, and pepper. Bring the mixture to a simmer.
Add the refrigerated tortellini to the simmering broth. Cook according to package directions, usually about 5 to 7 minutes, until the tortellini is tender.
Reduce the heat to low. Stir in the heavy cream until the broth becomes creamy. Do not let the soup boil after adding the cream.
Stir in the fresh spinach until it wilts into the soup.
Remove the pot from the heat. Stir in the Parmesan cheese until melted and smooth.
Serve immediately with extra Parmesan cheese on top.
Notes
For a slightly healthier option, substitute half-and-half for the heavy cream.
If you prefer using ground turkey or chicken sausage, the cooking time remains the same.
This soup is a great alternative to complicated meal planning when you need fast comfort food.