How to Grill a London Broil

Co-authored by Ollie George Cigliano

Last Updated: September 9, 2022 References Approved

What exactly is a London Broil? The answer to this question is actually somewhat murky — to some, "London Broil" is a cooking method; to others, the term refers to a specific cut of meat. Culinary pundits agree that the dish isn't even from London!^{[1]
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Research source} What's certain is this: London Broil is a flank steak dish that, when cooked correctly, is filling, flavorful, and nutritious. Though the London Broil can be cooked several different ways, marinating and slow-grilling the meat is an easy way to impart delectable texture and flavor.

Ingredients

Basic London Broil

2-2&1/2 pounds flank steak (serves about 6 people)
Salt and pepper to taste
Olive oil or canola oil

Balsamic Marinade

4 tablespoons balsamic vinegar
4 cloves of garlic, minced
3 tablespoons lemon juice
2/3 cup olive oil
3 tablespoon mustard
Red pepper flakes to taste
1 tablespoon soy sauce

Asian Marinade

3/4 cup soy sauce
5 cloves of garlic, minced
3/4 cup cilantro, chopped
1 tablespoon brown sugar
2 tablespoon sesame oil

Tequila Jalapeño Marinade^{[2]
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1 cup tequila
1 jalapeño pepper, seeded and chopped
1 cup teriyaki sauce
1 clove garlic
1/4 sesame oil
1/4 cup Worcestershire sauce
Salt and pepper to taste

Part 1

Part 1 of 3:

Preparing the Meat

1
Buy good-quality flank steak. There's no way around it; if you use high-quality meat, it's much easier to get a good-tasting result than if you use mediocre meat. While good chefs can make a tasty London Broil from a cheap piece of meat, this can be challenging, so opt for a high-grade piece of beef whenever you can. If you're unsure of which cuts of flank steak are the best, talk to your local butcher.
- In the U.S., the United States Department of Agriculture grades beef as "Select", "Choice", or "Prime" (in order of increasing quality). "Prime" cuts are generally the most flavorful and well-marbled, so you'll want to spring for these if they're available.
- Note that some butchers may label a cut of meat called top round steak as London Broil, rather than flank steak.
2
Tenderize your meat. Flank steak sometimes has an unfair reputation as a tough, chewy, and flavorless cut of meat.^{[3]
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Research source} However, this is only true if the meat is poorly-prepared. A number of ways can make flank steak tender before you even begin to cook it. The easiest? Hit it with a tenderizing mallet on a clean cutting board. This breaks up the meat's tough muscle fibers, giving it a softer texture.
- Don't use powdered meat tenderizers or tenderizing compounds containing extracts from papaya or pineapple fruits. These are tricky to use correctly and can sometimes tenderize the meat unevenly, giving it a mushy exterior and a tough interior.^{[4]
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3
Marinate your meat. Banging your flank steak with a hammer isn't the only way to make it more tender. For instance, flank steaks can benefit greatly by soaking them in a marinade before cooking — doing this not only gives the meat a chance to absorb the marinade's flavor, but also tenderizes it slightly (though this isn't true 100% of the time).^{[5]
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- You can marinate your meat for up to 24 hours—in fact, 12 hours is a great sweet spot.^{[6]
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- We've included a few sample marinade recipes above. To marinade your meat, combine the ingredients in one of the recipes above (or your own), put your meat in an airtight plastic bag, pour the liquid ingredients over it to cover it and seal the bag. Finally, leave it in the fridge for at least a few hours. Usually, about half a day of marinating will allow the meat to absorb as much flavor as possible.^{[7]
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- To help the flank steak absorb its marinade, score the meat before marinating it. Use a sharp knife to make a few X-shaped cuts on the surface of the meat about a half inch or so deep before applying the marinade.
4
Heat your grill. When the meat has marinaded a sufficient length of time, remove it from the refrigerator and let it start to warm to room temperature. While you wait, start your grill. Let it reach a medium heat before you cook your meat — you want the grill hot enough to give the meat an initial "searing", but not so hot that it dries out your meat during cooking.
- For optimal tenderness, you want to use long, slow cooking after the initial sear. On a gas grill, this is easy — simply set one burner to "medium" and one to "low". On a charcoal grill, this is a little trickier — you want to make a large pile of charcoals on one side of the grill and a small one on the other side.
- For charcoal grills, don't forget that the charcoals aren't ready to cook when they're flaming, but rather, when they're ashed-over and exuding an orange glow.

Part 2

Part 2 of 3:

Grilling Your Meat

1
Lay your meat directly on the grill. Remove your (now roughly room temperature) meat from the marinade and use a paper towel to blot your meat so that it is somewhat dry. Paint the bars of the grill lightly with a little olive or canola oil, then gently lay your meat down. You should immediately hear a sizzling sound — if you don't, your grill probably isn't hot enough. Let your meat cook with the grill uncovered.
2
Turn once during cooking. Resist the urge to turn the meat frequently — doing this can dry the meat out. The exact amount of time each side of your meat will take to cook can vary greatly based both on the level of "done"-ness you're looking for and on the thickness of your meat. In general, thicker cuts will require a few more minutes per side, as will (obviously) more well-done dishes. Below are some general guidelines for how long to spend cooking your meat per side:^{[8]
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- For rare: 2 minutes for a 1/2 inch (1.27 centimeter) steak, 2-3 minutes for a 3/4 inch (1.9 centimeter) steak, 3-4 minutes for a 1 inch (2.54 centimeter) steak.
- For medium: 3-4 minutes for a 1/2 inch steak, 4-5 minutes for a 3/4 inch steak, 5-6 minutes for a 1 inch steak.
- For well-done: 5-6 minutes for a 1/2 inch steak, 6-7 minutes for a 3/4 inch steak, 8-9 minutes for a 1 inch steak.
3
Optionally, transfer to low heat. If you divided your grill into a hot section and a cooler section (as directed above), once your meat starts to approach done-ness, if you like, you can transfer it to the cooler section. Leave it here for several more minutes with the grill cover closed. Cooking the meat for a longer period of time over lower heat helps get it as tender as possible — this is why exceptionally tough cuts of beef like brisket are sometimes cooked at low heat all day.
4
If you haven't marinated, paint with your favorite sauce. If you didn't have time to apply a marinade before cooking, you still have a chance to give your meat some extra flavor during the cooking process. Using a grill brush and a small bowl of your favorite sauce, paint the top side of the meat generously, then repeat after you flip it. Give each side another application of sauce about thirty seconds before you plan to remove the meat from the grill. While the complex flavor combinations that are possible with marinades aren't possible with this trick, a piece of meat that's been generously basted with barbecue sauce, sriracha, or another delicious sauce can be outstanding in its own right.
5
Remove your meat when it's cooked through. The meat is done when it has a pleasing brown color (flecked with black) and a utensil inserted into the thickest part of the meat doesn't encounter any tough, uncooked portions. If you're unsure about whether your meat is done or not, don't be afraid to cut into it to look for any deep red uncooked portions.
- Another way to check your meat for done-ness is to use a thermometer. Inserted into the thickest part of the meat, a thermometer should read about 135^o F (about 57^o) for medium rare; up to ten degrees more for medium to well done.^{[9]
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  Research source} Any hotter than this and the meat can begin to dry out, so remove it immediately!

Part 3

Part 3 of 3:

Serving Your Meat

1
Allow the meat to "rest" before cutting it. As with most other cuts of meat, flank steak is at its most tender and flavorful not right after it comes off the grill, but after it's had a little time to rest and cool. If the meat is cut immediately after it's removed from the grill, you'll notice its internal juices spill onto the plate. These juices are responsible for the meat's flavor and texture, so doing this can make your meat lest tender and tasty. However, if you give your meat a short "break" before cutting into it, it has a chance to re-absorb these juices, retaining much of its moisture and flavor.
- To "rest" your meat, place it on a clean plate or platter under tented aluminum foil and let it sit for 10-15 minutes. The foil will help the meat retain its heat as it rests.
2
Slice against the grain. Flank steak is made up of long, thin muscle fibers — you can see them if you look for small, faint lines running the length of the meat. If left intact, these fibers can be tough to chew. However, by cutting the meat diagonally, perpendicular to the grain of the meat, the fibers are severed, making the slices of meat much more tender. For this reason, London Broils are traditionally served as narrow diagonal slices made against the grain of the meat.
3
Season as desired. Divide your London Broil into a portions consisting of a few slices each. If you wish, you can now season your portions individually. A light sprinkling of salt and fresh-ground black pepper almost always pairs well with London Broil, but other seasonings can make great choices as well. Below are just a few seasoning ideas:
- Pre-made seasoning mixes (Johnny's, etc.)
- Rosemary, thyme, and roasted garlic
- Chili powder
- Paprika
- Grilled/fried onions
4
Enjoy! Congratulations! Your delicious London Broil is all ready to eat. Try serving this classic dish with roasted vegetables or sandwiching it between a few pieces of bread for classic flavor combinations.

Community Q&A

Question

My London broil is 1-3/4 inches thick. How long do I cook it for medium rare on a charcoal grill?

Penmouse

Community Answer

The USDA recommends beef steaks be cooked to 145 degrees F or 62.8 degrees C. Allow the steak to rest a minimum of 3 minutes before serving. Use an instant read thermometer to check the steak temperature. I could not find cook time that was not associated with a brand name so I cannot give an exact cook time. You can check a cookbook for help or search online to determine the actual cook time.

Warnings

Don't pierce your meat with a fork to turn it. Instead, rotate and flip your meat using long-handled tongs. Piercing your meat can release the internal juices, leading to a drier finished product.

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