After soaking in the herbs and a few other fresh ingredients, the flank steak becomes tender and intensely flavored. It's fantastic served with a side salad for an outdoor barbecue, or indoor dinner party.
*Please note that most of the prep time is marinating/refrigeration time.
In a small mixing bowl, combine all of the ingredients except the rosemary sprigs and the steak. Cut any excess fat off of the steak and place it on a large flat plate. Add half of the marinade to one side and half to the other -- making sure the entire piece of meat is well coated. This marinade is thick and works much like a rub -- so rub it in! Then place it in a large zip-lock bag along with the rosemary sprigs and what's left of the lemon. Place it in the refrigerator for at least 3 to 6 hours. (Overnight is okay.)
About 10 minutes before you're ready to grill, remove the steak from the fridge to bring it closer to room temperature. Preheat the grill and season the meat on both sides with salt and pepper. Place the steak on the grill once it's very hot. If you don't hear a nice, strong sizzling sound when the meat hits the grill, wait! You must wait for the sizzle! If you don't, the steak won't caramelize and brown properly, to form a beautiful crust. So....when your steak sizzles, cook it on each side for about 4 minutes. Do not move it until you're ready to flip it over. It will be medium-rare, which I think is perfect for flank steak.
Place the steak on a platter, cover with foil, and let it rest for at least 10 minutes to allow the juices to settle. Then, slice the steak thinly against the grain and serve!