Heat up your pot to medium heat, and add in your butter. Add in your sausage and break apart.
Once the sausage is almost fully cooked, add in your onion and garlic. Sauté for about 3 to 5 minutes. Add in the Italian seasoning, salt, pepper, chili flakes, tomato paste, and flour. Stir and let that cook for about 2 minutes.
Add in the crushed tomatoes and chicken broth. Stir and let come to a boil. Then turn the heat to a simmer and cover. Let that simmer for about 15 minutes. While that's cooking, boil your tortellini in a separate pot according to the instructions on the back.
After the 15 minutes, add the tortellini, heavy cream, and kale or spinach to the pot. Let that simmer together for a few minutes. Taste test to see if it needs more salt. Add a good amount of Parmesan to your bowl to top it off.
