Flank steak is an odd cut of beef. I don’t care what anyone says. It’s fairly lean, relatively affordable, and its texture has a coarse, ropy look. At first glance you might say, “No thanks, I’ll take the New York Strip!”
But flank steak, also known as London Broil, is a delightful cut of meat! It cooks quickly, takes marinades beautifully, and is easy to serve to a crowd! You’ve probably eaten it before and never realized it because it’s the cut most often used for fajitas.
The Secret to Tender, Juicy Flank Steak
You really need a three-pronged approach.
- Use acid in your marinade. It helps to break down proteins in the meat, making it more tender.
- Flank steak is lean. Like most lean meats you need to cook it fast and hot!
- Finally, slice it thin across the grain of meat, which shortens the muscle fibers, creating a more tender bite of meat.
What Makes a Good Flank Steak Marinade?
Flank steak needs a little acid to help tenderize the fibrous muscle and provide flavor. Do this, and you will have tender, succulent slices of beef. Skip this step, and there’s a good chance you’ll be chewing shoe leather.
Vinegar and lime juice are both great with flank steak. I also tested this recipe with buttermilk, but I personally didn’t care for it and thought the vinegar and lime juice did a better job of both seasoning and tenderizing the beef.
For this recipe, I used a combination of white wine vinegar and lime juice.
How Long Should I Marinade Flank Steak?
I came across some research that said you shouldn’t marinade flank steak longer than two hours because it could “scorch” or toughen the meat. The reason you’ll see this is because acid breaks down proteins, and when those proteins break down too much water is released and the muscle becomes tough.
But marinades in tighter cuts of meat like flank steak really don’t penetrate deep into the tissue like they would with fish, so you have a little more leeway.
I tested this marinade after two hours, and again after eight hours. Both times the meat was tender and flavorful. I also tried it after 24 hours and found the meat a little tough compared to the others. Just to be on the safe side, I wouldn’t marinade this overnight.
Can You Marinade and Freeze Flank Steak?
Feel free to freeze this steak with the marinade! Make the marinade in a zip top bag, add the steak and turn to coat. Squeeze as much air out as possible, then store it in the freezer for up to 3 months.
Take the steak out of the freezer and thaw it in a bowl of water a couple of hours before you want to grill it or the morning before you plan to grill it.
How to Grill Flank Steak
Flank steak is an odd shaped cut where one end is usually thicker than the other by as much as an inch. This alone can make cooking it a challenge, but this is actually an easy problem to solve using one of two methods.
- Method 1: Pound it thin. Cover the surface of the steak with parchment or plastic wrap. Then use either a meat mallet or heavy skillet to pound the thickest part of the steak until it’s closer in size to the thinner parts. Then marinade as directed.
- Method 2: Cook it over two heat zones. Create a hot and warm zone in your gas or charcoal grill. Place the thickest part of the steak on the hot zone, and the thinner part over the warm zone. This is my preferred method.
How Long to Grill Flank Steak
Lean cuts of meat like flank steak are really best when served medium rare. If you cook it to the medium stage or beyond, the meat is tough and chewy rather than juicy and succulent, so shoot for medium rare even if it’s not your normal range.
Remember, too, that time is variable. To get a perfectly cooked steak every time, insert a meat thermometer through the side of the thickest part of the steak.
- Medium: 8 minutes per side (145°F)
- Medium Rare: 6 to 7 minutes per side (135°F)
- Rare: 5 to 6 minutes per side (125°F)
These times are based on cooking the steak with the two-zone method, not the method of pounding the meat thinner. The cooking times may be faster if you used the pounding method.
Need More Grilled Meat? Try These!
- This Flank Steak uses soy sauce.
- Quick and easy Grilled Steak Skewers.
- Grilled Ribeye with herbed butter sauce is always a win!
- Looking for a good burger? Try this!
- Mushroom and Swiss Cheese Burger? Yes, please!
- 1 1/2 - 2 pound flank steak
- For the marinade:
- 1/4 cup white wine vinegar
- Juice from half lime
- 4 large cloves garlic, minced
- 2 tablespoons Worcestershire sauce
- 2 tablespoons honey
- 2 teaspoons smoked paprika
- 2 teaspoons chili powder
- 1 1/2 teaspoons kosher salt
- 1 teaspoon dried thyme
- 1 teaspoon cumin
- 1 teaspoon freshly cracked pepper
- 1/2 teaspoon crushed red pepper flakes
Make the marinade
In a dish large enough for the flank steak to lay flat combine vinegar, lime juice, garlic, Worcestershire sauce, honey, smoked paprika, chili powder, salt, thyme, cumin, ground pepper, and red pepper flakes. Just use a fork or whatever you have lying around to mix it all together.
Coat the steak
Once the marinade is mixed together, toss the steak in the marinade and turn a few times to make sure the surface area is coated. Cover and place it in the fridge for at least 2 hours and as long as 8 hours.
Preheat the grill
Prepare a charcoal grill for two-zone grilling, so half is hot and the other half is warm. The grill is hot when you can only hold your hand over the hot zone for a second or two.
On a gas grill , heat the grill to 450°F with two burners going, which should only take about 10 minutes, then turn one of the burners down to medium to create two cooking zones.
Grill the steak
Remove the steak from the marinade. Discard the marinade. Put the thickest part of the steak over the hottest side of the grill, and the thinner side over the warm zone. Close the lid and sear for 7 minutes. Open the lid, flip the steak, close the lid. Cook for an additional 6 to 7 minutes. Meat should be medium to medium rare.
Rest and slice
Let the steak rest for about 5-10 minutes. Then cut into thin slices (less than 1⁄2 inch thick), at a diagonal angle across the grain. Arrange on a platter and serve.