Mix meat and salt. Shape mixture into 4 patties, each about 3/4 inch thick. Press pepper into both sides of the patties. Cook patties in a large skillet over medium-high heat, turning once, till the desired doneness is reached, about 8 minutes. Drain off the fat. Sprinkle the cognac over the patties and immediately ignite, if desired. Remove patties to a warm platter. Stir wine into drippings in skillet. Heat just to boiling, stirring constantly. Whisk butter, small pieces at a time, into the sauce. Serve sauce over the patties.