The flat iron is named for its distinctive shape, which looks a
bit like an antique iron with its handle missing. This unique
portion of the chuck shoulder clod is unusually tender and
marbled.
The flat iron has a thick layer of very tough silver skin that
runs through the middle, bisecting the muscle in half. Because of
this silverskin, the flat iron is unusable whole. It cannot be
braised or slow roasted, but instead must have the meat cut away
from the membrane.