Bring a large pot of salted water to a rolling boil and cook the rigatoni according to package directions until al dente (usually 9–12 minutes). Drain and set aside, reserving about 1/2 cup of pasta cooking water.

While the pasta cooks, heat a large skillet over medium-high heat and add the olive oil. Let the oil shimmer but not smoke.

Add the Cajun-seasoned steak tips to the hot skillet in a single layer and cook until well-browned on one side, about 2–3 minutes, then flip and brown the other side.

If desired, check the internal temperature of steak tips to achieve preferred doneness (medium-rare 130–135°F). Remove from skillet and tent loosely with foil to rest.

Reduce the skillet heat to medium. Pour in the heavy cream, scraping up any browned bits from the bottom of the pan.

Gradually sprinkle in the Parmesan cheese, stirring continuously until the sauce is glossy and velvety. If thick, add reserved pasta water to adjust the consistency.

Return the rigatoni to the skillet and toss to coat in the sauce. Fold in the rested steak tips.

Plate while hot and garnish with chopped parsley before serving.