In 2002, some researchers discovered an impressive new cut of meat, trimmed from the shoulder area, a place more traditionally associated with cheaper cuts of beef. The researchers discovered that if the connective tissue was trimmed off in a certain way, the cut left behind was flavourful and punched way above its weight when compared to more costly cuts of steak. Uniform in thickness and rectangular in shape - the jackpot! The second most tender beef muscle after Fillet.
Over a period of time the so called Flat Iron Steak (because it looks like an old-fashioned metal flat iron) became hugely popular with the American public, thanks mainly to the fact that it was so cheap. So top restaurants took it on and it all escalated from there.
Flavourful, juicy, well-marbled but lean steak, best cooked rare or medium rare in the classic method (very, very hot pan or grill; both sides sealed and rested well in a warm place).