live in an area where selling it in strips or cubes is the norm
(such as New England), instead ask the butcher to sell you a
whole trimmed flap. This gives you more options when you
get it home. As it is a relatively lean cut, there’s not really
any need to spring for Prime-grade flap; the Choice stuff
will taste just as good and costs less.
Trimming: Flap meat generally requires very little trimming;
remove any silverskin.
Cooking: More so than any other cut I know of, flap meat is
pretty terrible when it’s cooked rare. You can see for
yourself when it’s still raw: this is some mushy-ass meat.
Only by cooking it to medium-rare or medium can you get it
firm enough to not squish around in your mouth as you
chew it.
Flap meat works particularly well on the grill. It doesn’t
require the extreme heat of skirt steak, and it doesn’t have
the fat flare-up problems of short ribs, which makes it pretty
simple to cook. Just build a hot fire on one side of the grill,
lay on the flap (after seasoning it, of course), and flip every
minute or so until it gets to at least 125°F at its thickest part.
Slicing and serving: Flap meat has an extremely coarse
grain with an obvious direction: it runs crosswise all the way
down the steak. This makes it hard to cut against the grain
into thin bite-sized pieces (you’d end up with strips sliced
lengthwise). Instead, the best thing to do it first divide it into
three or four pieces, slicing with the grain, then to rotate
each of those pieces 90 degrees and thinly slice them