Heat a large stock pot or dutch oven over medium-high heat. Break sausage into small pieces into pot. Cook until brown, about 3 minutes. This may need to be done in batches. Remove from pot and set aside until ready to use.
To the same pot, add butter. Add onion, and sauté for 3 minutes. Reduce heat to medium, and add garlic, and cook until fragrant, about another 3 minutes. Stir in crushed red pepper and Italian seasoning. Stir in flour and stir until smooth. Return sausage to pot, and all contents together.
Stir in chicken broth/stock and tomato sauce. Add salt and bay leaves. Cover with lid, and simmer for 10 minutes.
Add tortellini to pot, along with heavy cream and parmesan cheese. Continue to cook for 5 - 7 minutes, or until noodles are al dente, and cheese has melted.
Turn off heat, and stir in kale. Serve warm.
