Preheat oven to 450; heat a nonstick ovenproof skillet over medium.
Combine 2 tablespoons brown sugar, pepper, and salt in a bowl. Press sugar mixture onto both sides of steak, then sear meat on one side until browned, about 5 minutes. Flip steak and brown second side for 2 minutes. Transfer skillet to oven to finish cooking (about 8 minutes for medium rare). Remove steak, tent with foil, and let meat rest 5 minutes.