Cook the fettuccine or penne according to package instructions until al dente.

In a skillet, melt the unsalted butter over medium heat and sauté minced garlic until fragrant.

Add the ribeye steak to the skillet and cook to your desired level of doneness, then slice into pieces.

Pour in the heavy cream and bring to a simmer, stirring to combine with steak.

Stir in the grated Parmesan cheese until melted and creamy.

Add the fresh spinach and cook until wilted.

Drain the pasta and add it to the skillet, tossing to coat in the sauce.

Season with salt, pepper, and crushed red pepper flakes to taste.