01 - In a small bowl, combine the softened butter, minced garlic, parsley, thyme, rosemary, lemon zest, and a pinch of salt. Mix thoroughly. Shape into a log using plastic wrap and refrigerate until firm, approximately 10 minutes.
02 - Preheat your oven to 400 degrees Fahrenheit.
03 - Pat the filet mignon steaks dry with paper towels. Rub with olive oil and season generously with salt and black pepper on all sides.
04 - Heat a heavy ovenproof skillet over high heat until very hot. Sear the steaks for 2 to 3 minutes per side, forming a golden-brown crust.
05 - Transfer the skillet to the preheated oven. Roast for 4 to 6 minutes for medium-rare, or to your preferred doneness. Use a meat thermometer for accuracy: 130 to 135 degrees Fahrenheit for medium-rare.
06 - Remove the steaks from the oven and transfer to plates. Immediately top each steak with a generous slice of garlic herb butter. Rest for 5 minutes before serving.