Preheat an outdoor grill to high heat (about 500 degrees). Sear steaks for 3 minutes per side. Reduce the heat to medium-low and continue cooking with the lid closed until the steaks reach the desired level of doneness (130 degrees F for medium-rare). When the steaks are removed from the grill, immediately top with 1 tablespoon butter each, tent with aluminum foil, and allow the steaks to rest 5 to 10 minutes before cutting into them.