Skirt steaks come from two different muscles and are sometimes labeled as inside skirt steak or outside skirt steak. The more desirable outside skirt steak measures 3 to 4 inches wide and 1/2 to 1 inch thick. Avoid the inside skirt steak, which typically measures 5 to 7 inches wide and 1/4 to 1/2 inch thick, as it is very chewy. Skirt steak is most tender when cooked to medium (130 to 135 degrees). Thin steaks cook very quickly, so we recommend using an instant-read thermometer for a quick and accurate measurement.