Bring a large pot of salted water to a boil. Cook the rigatoni until al dente. Drain and set aside.
Season steak cubes with Cajun seasoning. In a skillet with olive oil over medium-high heat, sear steak until browned. Set aside.
In the same skillet, lower heat to medium and sauté garlic until fragrant. Add beef broth and cream. Stir in paprika, salt, and pepper. Simmer 2-3 minutes.
Add Parmesan and stir until melted and smooth.
Toss in rigatoni and coat with sauce. Return steak and mix. Heat for 1-2 minutes more.
Serve hot, topped with more black pepper and Parmesan if desired.
Notes
Use freshly grated Parmesan for the best melt and flavor. Adjust Cajun spice level to taste.