Bring a large pot of salted water to a boil. Add 8 ounces of fettuccine and cook according to package instructions until al dente, usually about 10-12 minutes. Reserve 1/2 cup of pasta water before draining. Set the pasta aside, covered, to keep warm.
While the pasta cooks, season your steaks generously with salt on both sides. Heat 1 tablespoon of olive oil in a heavy skillet over medium-high heat. Once hot, add the steaks and sear for about 3-4 minutes per side for medium-rare, or longer depending on your preference. Remove the steaks to a plate and let rest for 5 minutes before slicing thinly against the grain.
In the same skillet, add the sliced mushrooms. Sauté for 5-7 minutes until soft and golden. Add the minced garlic and freshly cracked black peppercorns (1 teaspoon), cooking for another 1-2 minutes until fragrant.
Lower the heat to medium and pour in 1 cup of heavy cream. Stir to combine and allow the sauce to thicken slightly, about 3-5 minutes. Stir in 1/2 cup grated Parmesan cheese until melted and smooth. If the sauce is too thick, add a splash of reserved pasta water to loosen it.
Add the cooked fettuccine to the skillet and toss gently to coat the noodles with the creamy sauce. Then fold in the sliced steak, allowing it to warm through for a minute or two. Taste and adjust seasoning with salt or additional pepper if desired.
Serve the pasta hot, garnished with freshly chopped parsley for a burst of freshness and color.
