The unique flavor in this flank steak comes from jalapeño powder - a potent green powder that is literally made from fresh jalapeños! If you can't find it, try using fresh chopped jalapeños for a similar flavor. NOTE: Flank steak is meant to be cooked rare to medium-rare, and will become tough if cooked longer. Don't forget to slice across the grain of the meat. Flat Iron Steak works great with this too!