Bring a large pot of salted water to a boil and cook the tortellini for 2-3 minutes or until al dente; drain and set aside.
Heat olive oil in a large heavy-bottomed skillet over medium-high heat until shimmering.
Season steak cubes with salt and half of the cracked pepper, then sear in the skillet for 3-4 minutes until browned; remove steak and set aside.
Reduce heat to medium and add butter to the same skillet, followed by the cracked garlic cloves.
Sauté garlic for 2 minutes until golden and fragrant, taking care not to burn.
Deglaze the skillet with heavy cream, scraping up the browned bits from the bottom of the pan.
Simmer the cream for 5 minutes until slightly reduced, then whisk in the parmesan cheese and red pepper flakes until smooth.
Return the steak and cooked tortellini to the skillet, tossing for 1-2 minutes until the sauce coats the components evenly.
Finish with remaining cracked black pepper and fresh parsley before serving.