Bring 4 quarts of salted water to a boil and cook rigatoni until al dente; drain and set aside.
Pat steak cubes with paper towels to remove surface moisture and season with salt and black pepper.
Heat olive oil in a large cast-iron skillet over high heat until it reaches its smoke point.
Add steak cubes in a single layer and sear without moving for 2 minutes to achieve Maillard browning; flip and cook for an additional 90 seconds.
Reduce heat to medium-low, add butter and minced garlic to the skillet, and baste the steak for 60 seconds until fragrant; remove steak and butter from the skillet.
In the same skillet, combine marinara sauce, heavy cream, and red pepper flakes; simmer over medium heat for 3 minutes.
Incorporate the cooked rigatoni, 1 cup of mozzarella, Parmesan, and half of the crumbled bacon into the sauce, tossing until the cheese is incorporated.
Top the pasta with the remaining mozzarella and bacon, then cover with a lid for 2 minutes until the cheese is fully melted.
Distribute the garlic butter steak bites over the pasta and garnish with fresh parsley before service.