Step 1: Bring steaks to room temperature for at least 30 minutes. Pat thoroughly dry with paper towels. Season generously on both sides with salt and black pepper.
Step 2: Heat a heavy-bottomed skillet (cast iron preferred) over medium-high heat until it just begins to lightly smoke.
Step 3: Add 1 tablespoon high smoke point oil to the pan, swirling to coat. Carefully place the seasoned steaks in the hot pan. Sear for 2-3 minutes per side for medium-rare to medium doneness, until a deep golden-brown crust forms.
Step 4: Reduce heat to medium-low. Add 4 tablespoons of unsalted butter, 4 cloves of smashed garlic, 2 sprigs of fresh rosemary, and 2 sprigs of fresh thyme to the pan. As the butter melts and sizzles, tilt the pan slightly and use a spoon to baste the melted herb butter over the steaks continuously for 1-2 minutes.
Step 5: Remove steaks from the pan and transfer to a cutting board. Tent loosely with foil and let rest for at least 5-10 minutes. This is crucial for juicy steaks.
Step 6: While the steaks are resting, drain off most of the excess fat from the pan, leaving about 1 tablespoon along with the cooked garlic and herbs. Return the pan to medium heat.
Step 7: Add the remaining 2 tablespoons of unsalted butter to the pan. Once melted, add the 3-4 cloves of minced garlic and sauté for 30 seconds to 1 minute until fragrant, being careful not to burn it.
Step 8: Whisk in 1 tablespoon of all-purpose flour and cook for 1 minute, stirring constantly, to create a roux.
Step 9: Gradually whisk in 1 cup of chicken or beef broth, scraping up any browned bits from the bottom of the pan. Bring to a simmer, then whisk in 1 cup of heavy cream.
Step 10: Stir in 1/2 cup of grated Parmesan cheese and season with salt and black pepper to taste. Let the sauce simmer gently for 3-5 minutes, stirring occasionally, until it thickens to your desired consistency. Stir in 1 tablespoon of fresh chopped parsley.
Step 11: Slice the rested steaks against the grain into desired thickness.
Step 12: Arrange the sliced steak on plates and generously spoon the creamy garlic sauce over the top. Garnish with additional fresh parsley if desired. Serve immediately.