This is another one of those meals that I grew up eating. It's an absolute gem.
Flank steak is a flat, long-fibered piece of meat that comes from between the cow's ribs and the hips. While this cut of meat is flavorful, be sure you serve it by slicing it across the grain. If it is cut across the grain, the meat fibers are short and the meat will seem very tender. Cut with the grain and you will be working it for the next ten hours. The good news is that with flank steak, it is very easy to tell which way the grain is going because the fibers are easily visible.
I like using my mom's simple preparation. I marinate it in equal parts soy sauce and rice wine (not rice wine vinegar!). Before pouring the marinade over, I like to prick the meat with a fork a whole bunch of times. Let the steak marinate for thirty minutes to two hours.
Preheat the broiler to high and move the oven rack to the middle of the oven. You don't want the steak too close to the element or the outside will begin to smoke before the meat is done. Line a sheet pan with foil. Remove the steak from the marinade, let excess marinade drip off, and then place flat on the sheet pan. Broil, about 10-12 inches from the element until the top begins to show some nice browning (about 6-8 minutes). Flip the steak over and broil until the fresh side turns a nice golden color. You can use a thermometer to poke in the middle to be sure it is where you want it. I recommend shooting for rare to medium rare in the middle (140-150 degrees F). This means you will have a nice range of meat doneness. The ends, which cook quicker, will be more done.
Remove the meat from the oven and let rest for about ten minutes before cutting. As you can see in the picture above, I skipped that step. I tried to wait, but I was ravenous tonight. I suppose only having eaten two slices of bread and a handful of Fruity Pebbles all day will do that to a gal. Anyway. If you let it rest, the meat won't hemorrhage juice so badly all over your cutting board. We enjoyed this steak tonight with a rice pilaf and mixed vegetables. Boy was it ever good (and not just because I was starting to think about eating my shoes, either!).
Oh, and one last thing. If you're a fan of grilling, this can also be cooked on the BBQ. Just be sure the heat is relatively high. Flank steak is fairly thin, so you want the heat high enough to be able to sear the outside and get some nice color on it before over-cooking the inside.