Brown the Sausage: In a skillet over medium heat, cook the sausage until browned. Drain excess grease and transfer to the crockpot.
Add Ingredients: Pour in marinara sauce, diced tomatoes, chicken broth, garlic powder, onion powder, Italian seasoning, and red pepper flakes (if using). Stir well.
Slow Cook: Cover and cook on LOW for 4–6 hours or HIGH for 2–3 hours.
Add Tortellini & Cream Cheese: About 30 minutes before serving, add the cheese tortellini and cubed cream cheese. Stir to combine and cook until tortellini is tender.
Finish & Serve: Stir in fresh spinach (if using) and let it wilt for about 5 minutes. Serve hot with Parmesan cheese on top.