Preheat oven to 375 degrees. Using the bottom of a small skillet smash peppercorns. Press crushed peppercorns into steak until completely covered. Let sit for 30 minutes. Melt butter in a cast iron pan over medium heat. Season steak with salt and place in pan. Cook until dark brown on one side, flip, and cook on other side, approximately 3 minutes per side. Place steak in baking dish and finish in oven to desired degree of doneness, about 3 minutes. Melt butter in skillet and add shallots. Add a splash of cognac, cream and 1 teaspoon crushed peppercorns. Bring to boil and reduce sauce. Serve steak topped with sauce.