Flat iron steak is cut from beef shoulder. To make a flat iron steak, butchers remove the connective tissue to separate the top shoulder blade into two cuts: One is the top blade, the other is the flat iron.
Flat iron steak is nicely marbled and is less expensive than other steaks, which makes it a popular choice among home cooks. When it's cooked correctly, flat iron steak is wonderfully tender and juicy.