Pat steaks dry and season with salt and pepper. Heat oil in a well-seasoned large cast-iron skillet over moderately high heat until hot but not smoking, then cook steaks 6 minutes on each side for medium-rare. Transfer steaks to plates. Remove skillet from heat and immediately add butter and horseradish, stirring and scraping up any brown bits. Stir in Worcestershire sauce and spoon sauce over steaks.
