1. Heat 1 tablespoon of butter in a large skillet over medium-high heat. Season the steak with salt and pepper, then sear it for 2-3 minutes until nicely browned. Remove the steak from the skillet and set it aside.

2. In the same skillet, melt the remaining tablespoon of butter. Add the minced garlic and crushed red pepper flakes, cooking for about 1-2 minutes until fragrant.

3. Pour in the heavy cream and let it simmer for 3-4 minutes, allowing it to thicken slightly. Stir in the grated Parmesan cheese until it melts smoothly into the sauce.

4. Add the uncooked rotini pasta and water or broth to the skillet. Bring the mixture to a boil, then reduce the heat, cover, and simmer for about 10-12 minutes, or until the pasta is al dente.

5. Return the seared steak to the skillet and gently mix everything together until the steak is well coated in the creamy sauce. Adjust seasoning with salt and pepper to taste, then garnish with freshly chopped parsley.