Entraña (outer skirt) is what many know as the skirt steak. If you are familiar with skirt steak then you will know that it usually comes with a slightly thick layer of fat and muscle membrane; similar to what coats the cuts of vacio. Although trimming the surrounding membrane will make the meat easier on the teeth, it is typically left on. Leaving it on will help to keep the juices inside with a tasty crispy exterior. This method results in a chewier cut of skirt but very juicy.