Heat olive oil in a large pot over medium-high heat. Add beef sausage and cook until browned, about 6-8 minutes. Remove and set aside.
In the same pot, sauté diced onion, carrots, and celery for 8-10 minutes until soft. Add minced garlic and red pepper flakes; cook for 1-2 more minutes.
Stir in crushed tomatoes and simmer for 5 minutes.
Return the beef sausage to the pot, add chicken broth, Italian seasoning, bay leaf, thyme, salt, and pepper. Bring to a boil then reduce heat to low. Simmer for 20-30 minutes.
Add tortellini according to package directions (3-5 minutes). Stir in spinach until wilted.
Optionally stir in cream off heat for added richness.
Taste and adjust seasoning if necessary before serving warm with parsley and Parmesan cheese.