According to the Crowd Cow, skirt steak is a fatty cut of beef pulled from the "plate," an area just under the cow's ribs, and "inner" skirt steak is an inexpensive yet popular cut for fajitas, Philly cheesesteaks, sandwiches, and tacos. However, there's also the "outer" or "outside" skirt steak, and it's quite different from its sibling.

The outside cut of a skirt steak is thick and soft because it comes from the diaphragm muscle, which isn't worked very hard during the cow's life. In contrast, an inside skirt steak uses the transverse abdominal muscle, which is much tougher, so despite their similar names, these sections of beef need to be cooked differently.

The outside skirt steak is best-served medium-rare and is delicious when marinated, seasoned with a dry rub, or just sprinkled with herbs, while the well-marbled inside skirt steak is perfect to cook up for steak fajitas or spicy beef stir-fry. While inner skirt steak can be substituted for the outer skirt, you'll have to do some prep work first.

If you have to swap fatty outer skirt for the cheaper, tougher inner skirt, thoroughly pound the tougher steak to puncture the protein and even out the thickness. Another good step is to let the inner cut soak up a variety of spices and sauces to give it the same rich flavor as an outer cut, then sear it for a delicious, less expensive dinner.