Heat a large skillet over medium-high heat and add 2 tablespoons of olive oil and half of the butter. Sear the seasoned steak tips until browned, about 3-4 minutes.

In a large pot, bring salted water to a boil. Cook rigatoni according to package instructions until al dente, about 10-12 minutes.

Reduce heat in the skillet to medium, add the remaining butter, sauté garlic for 30 seconds, then mix in the heavy cream and simmer until slightly thickened.

Slowly stir in freshly grated Parmesan cheese until melted and smooth. Season with salt, pepper, and Cajun seasoning to taste.

Combine cooked rigatoni with the sauce, adding reserved pasta water if needed. Gently fold in the seared steak tips.

Plate the dish and garnish with additional Parmesan cheese and black pepper. Serve hot.