Combine first 3 ingredients in a small bowl, stirring well with a whisk. Set aside.
Heat oil in a large nonstick skillet over medium-high heat. Sprinkle steaks with salt and pepper; add steaks to pan. Cook 4 minutes on each side until steaks are medium-rare or desired degree of doneness. Transfer steaks to a serving dish, and keep warm. Pour sherry mixture into pan. Cook 1 to 1 1/2 minutes or until reduced to 2 tablespoons, stirring to deglaze pan; pour over steaks.