In a large pot of boiling salted water, cook the rigatoni according to package instructions until al dente. Reserve 1/2 cup pasta cooking water, then drain and set aside.

In a large skillet, heat the olive oil over medium-high heat. Add the Cajun-seasoned steak tips and cook until browned and cooked to your liking, about 4 to 5 minutes total. For food safety, aim for at least 145 F for whole cuts of beef, then rest briefly. Remove the steak from the skillet and set aside.

In the same skillet, reduce heat to medium and add the minced garlic. Sauté about 30 seconds until fragrant, taking care not to burn it.

Pour in the heavy cream and bring to a gentle simmer. Stir in the grated Parmesan cheese off the heat or on very low heat until melted and smooth. If the sauce is too thick, add a splash of the reserved pasta water to loosen it. Season with salt and pepper to taste.

Toss the cooked rigatoni in the sauce until well coated, adding a tablespoon or two of reserved pasta water if needed to achieve the desired consistency.

Add the steak tips back into the skillet and mix gently so the pieces warm through and pick up the sauce.

Serve warm, garnished with fresh parsley.