Remove the Italian sausage from its casings and set aside. Bring a large pot of salted water to boil for the tortellini.

Heat olive oil in a large skillet over medium-high heat. Add the crumbled sausage and cook for 6-8 minutes, breaking it apart with a wooden spoon, until browned and fully cooked. Transfer the sausage to a plate using a slotted spoon.

Reduce heat to medium and add minced garlic to the same skillet. Sauté for about 1 minute until fragrant.

Pour in the chicken broth and scrape up any browned bits from the bottom of the pan. Let it simmer for 2 minutes to reduce slightly.

Add the heavy cream, Italian seasoning, and red pepper flakes if using. Stir well and bring to a gentle simmer. Let it cook for 3-4 minutes, stirring occasionally.

While the sauce simmers, cook the tortellini according to package directions in the boiling water. Fresh tortellini typically takes only 2-3 minutes. Drain and set aside.

Reduce the sauce heat to low and gradually stir in the Parmesan cheese until melted and smooth. Season with salt and pepper to taste.

Return the cooked sausage to the skillet and add the drained tortellini. Gently toss everything together until the pasta is evenly coated with the creamy sauce.

Garnish with fresh chopped parsley and additional Parmesan cheese. Serve immediately while hot and creamy.