01 - Remove steaks from refrigerator 30 minutes before cooking to reach room temperature. Pat dry thoroughly with paper towels.
02 - Generously season both sides of each steak with kosher salt and freshly ground black pepper, pressing the seasoning into the meat.
03 - Heat olive oil in a large cast iron skillet over high heat until shimmering and slightly smoking.
04 - Add steaks to the hot pan and sear for 3-4 minutes per side for medium-rare doneness. Remove from pan and tent loosely with foil to rest.
05 - Reduce heat to medium. Add butter to the same skillet and let melt. Add minced garlic and sauté for 1 minute until fragrant but not browned.
06 - Pour in beef broth and scrape up any browned bits from the bottom of the pan with a wooden spoon.
07 - Stir in heavy cream and bring to a gentle simmer. Let cook for 2-3 minutes until slightly thickened.
08 - Add Dijon mustard and Parmesan cheese, stirring constantly until smooth and melted. Stir in chopped parsley and season with salt and pepper to taste.
09 - Slice the rested steaks against the grain and arrange on plates. Spoon the creamy garlic sauce generously over the top and garnish with additional fresh parsley if desired.