Cook the pasta in a large pot of generously salted boiling water according to package instructions until al dente. Reserve a cup of pasta water before draining. Drain and set aside — do not rinse.

Heat olive oil in a large skillet over medium-high heat until shimmering.

Add the steak pieces in a single layer and season with salt and freshly ground black pepper. Cook for 4–5 minutes until browned, turning once halfway through. Remove from the skillet and set aside.

Reduce heat to medium. Add the minced garlic to the same skillet and sauté for about 1 minute until fragrant, stirring frequently.

Stir in the Cajun seasoning and red pepper flakes. Cook for 30 seconds to toast the spices and release their oils.

Add the butter and allow it to melt completely, stirring to incorporate with the garlic and spices.

Pour in the heavy cream while stirring continuously. Bring to a gentle simmer over medium heat — do not allow it to boil aggressively.

Stir in the grated Parmesan cheese until fully melted and the sauce is smooth and creamy.

Return the cooked steak to the skillet. Add the drained pasta and toss until everything is evenly coated in the sauce.

Cook for an additional 2–3 minutes until heated through. Adjust seasoning with additional salt and pepper if desired.

Garnish with chopped fresh parsley and serve immediately.