Step 1

Marinate the steak: Combine the marinade ingredients in a large non-reactive bowl.Place steak in the bowl and turn so that it is completely coated with the marinade. (You can also place the steak and marinade in a freezer bag and place it in a bowl.)Chill and marinate for at least 2 hours and up to overnight.

Step 2

your grill for high, direct heat with one part of the grill for lower, indirect heat. The grill is hot enough when you hold your hand about an inch over the hot side and you can only hold it there for about a second.

Step 3

Grill the steak: Remove the steak from the marinade and gently shake off the excess marinade from the steak (but make sure there is still a coating of it, you'll want the oil on it to help keep the steak from sticking to the grill).If you want, sprinkle generously on all sides with coarse salt and freshly ground pepper. The salt and pepper will help form a savory crust on the steak.Place steak on the hot side of the grill. Grill for a minute or two on each side to get a good sear, then move the steak to the cooler side of the grill, cover and cook a few minutes more until done to your liking. How do you know when the steak is done? One way to tell is to poke it with your fingertips. While the steak is still raw, test it with your fingers; it will be quite squishy. That's what a very rare steak feels like. Touch the tip of your nose and that's what a very well done steak feels like. Here's a visual guide, the finger test to check the doneness of steak.Otherwise use a good meat thermometer (I recommend a thermapen.)  Pull the steak off the grill at 120 to 125°F for rare, 130-140°F for medium rare, and 145°F for medium.

Step 4

Rest the steak: When the steak has cooked to your preferred level of doneness, remove from the grill and place on a cutting board. Cover with aluminum foil to hold in the heat while the steak rests for 10 to 15 minutes.

Step 5

Slice across the grain: Notice the direction of the muscle fibers of the steak; this is called the grain of the meat. Flank steak is a very lean cut that will be tough and chewy unless you cut it in a way that breaks up the muscle fibers.So, cut the steak across the grain of the meat, at a steep diagonal, so that the slices are wide. I find it easiest to use a long serrated bread knife for this, but any long sharp knife will do. If you want, you can take the excess marinade and bring it to a boil, simmer for several minutes, and serve with the flank steak. Great also with salsa or horseradish sauce.