Brown the ground sausage with the diced onion over medium high in a large stock pot or dutch oven. Break up the sausage as it browns and cook until the sausage is no longer pink (5-7 minutes).
Drain off any excess grease.
Add in the minced garlic and cook until you can smell the garlic (approximately 1 minute).
Add in the butter and cook until it melts.
Stir in the flour and sauté for 1 more minute.
Add in the chicken broth, tomato sauce, Italian seasoning, salt, pepper and red pepper flakes.
Bring the mixture to a boil. Stir in the tortellini and cook for cook for 3-4 minutes until tender.
Stir in the chopped spinach, parmesan cheese and heavy cream. Heat for a few minutes until the spinach is wilted.
Taste test and adjust the seasoning based on your preference.
Serve immediately while warm and enjoy!
