Combine all ingredients in a glass or ceramic dish. Remove flank steak from package and give it a quick rinse. Coat both sides of the meat with marinade. Refrigerate for at least 3 to 6 hours.Remove the steak from the marinade and place on a plate while you heat up the grill pan. Make sure to turn on your overhead exhaust fan as the cooking process can be quite smoky. When the pan is extremely hot, place the steak on a slight angle as this makes for more appealing grill marks. Cook without touching for about 1 ½ to 2 minutes. Rotate the meat about 45 degrees, keeping it on the same side, and cook for another 1 ½ minutes.Now flip it to the other side. Cook using the same method on the other side, cooking for 1 1/2 minutes, then rotating it and finishing the cooking process. I cook the flank streak to medium rare, which usually takes about 5 to 7 minutes total cooking time. Remove the meat to a cutting board and let it rest for a few minutes before slicing.When you’re ready, thinly slice the meat against the grain. That means find the directional striations/lines in the meat grain and slice perpendicular to it. Controversial Optional Sauce: Before grilling the flank steak, strain the marinade into a small saucepan. Discard what stays in the sieve. Add ½ cup of water to the marinade. Boil the marinade while heating the grill for the meat AND add an additional 10 minutes. The point of boiling, obviously, is to take away any risk of bacteria from the marinade. Also, by boiling for ten to fifteen minutes, the sauce will reduce and slightly thicken. Then just spoon a little into a dish and use it as a dipping sauce for the meat.