Flank steak is from the beef flank primal cut. It's very flavorful, but is one of the tougher cuts of beef. It can be prepared by braising or it can be grilled. It should be grilled on a very hot grill for a short time, then let it rest, and then slice it against the grain. Small flank steaks are approximately 1.0 pound and large flank steaks are 1.5 pounds.