Prepare the Beef: Pat the beef slices dry with paper towels. Season generously with salt and pepper.

Sear the Beef: Heat 1 tablespoon of olive oil in a large skillet over high heat. Once the oil is shimmering, add the beef in a single layer (work in batches if necessary). Sear for 1-2 minutes per side, until nicely browned. Remove the beef from the skillet and set aside.

Sauté the Garlic: Add the remaining 1 tablespoon of olive oil and the butter to the skillet. Reduce the heat to medium. Add the minced garlic and cook for about 30 seconds, until fragrant. Be careful not to burn it!

Create the Roux: Sprinkle the flour over the garlic and cook for 1 minute, stirring constantly to form a roux. This will help thicken the sauce.

Deglaze the Pan: Gradually whisk in the beef broth, scraping up any browned bits from the bottom of the pan. Bring to a simmer and cook for 2-3 minutes, until the sauce has slightly thickened.

Add the Cream and Parmesan: Stir in the heavy cream, Parmesan cheese, Italian seasoning, and red pepper flakes (if using). Reduce the heat to low and simmer for 2-3 minutes, until the cheese is melted and the sauce is smooth and creamy. Season with salt and pepper to taste.

Combine and Serve: Add the seared beef back to the skillet and toss to coat with the sauce. Cook for 1-2 minutes, until the beef is heated through. Serve immediately over cooked pasta, garnished with fresh parsley and additional Parmesan cheese.