From our Ask the Chef series.
Question: I would like to know what is the difference between flank and skirt steaks? Which one would be more tender, with great flavor and taste even if cold or well done? I know one has a membrane that makes it a little tougher; which one is it?
Answer: The difference really lies in where these cuts come from in the cow, but even that itsn’t too far away (there’s a fun diagram at this link, with additional opinion).
Both skirt steak and flank steak have come into favor in recent years, perhaps due to chefs who got creative in order to use these less expensive cuts. These cuts are often used in fajitas, perhaps since you can get long strips and can tenderize it with some great seasonings (including citrus) without ruining the steak flavor.
The skirt steak, to answer your question, has the membrane to which you are probably referring. You should talk to a butcher and get some recommendations based on how you like your steak. So much of which steak to buy is a matter of personal preference as well as how it is tenderized, seasoned and cooked.
In our experience, both the skirt steak and flank steak should be cut across the grain and into strips for these best usage. We like the skirt steak for fajitas (and it’s often cut for that purpose in the store), seasoned with lime, lots of garlic, and fajita seasoning. We like the flank steak for Philly-style cheesesteaks, tenderized and then stir fried with onions, peppers, garlic, a little oregano, salt and pepper.
Hope that helps!
See How to Grill the Perfect Steak step-by-step instructions.