Grilling a London broil to medium-rare perfection depends on high heat and careful attention to the meat’s internal temperature. If you’ve ever wondered how to cook a London broil on the grill, you’re in the right place. This cut, often from the top round or flank, can be tough if mishandled. But with the right technique, you get a juicy, flavorful steak that slices beautifully against the grain. Let’s get straight to it.
London broil isn’t actually a specific cut of meat—it’s a cooking method. Butchers usually label a large, lean steak from the round or flank as London broil. Because it’s lean, it needs high heat and quick cooking. Overcooking turns it into shoe leather. So pay attention to timing and temperature.
What Is A London Broil?
First, understand what you’re buying. A London broil is typically a thick cut of beef, around 1 to 2 inches thick. It comes from a muscular part of the cow, so it has little fat marbling. That means it can dry out fast. The key is to cook it quickly over high heat and never past medium-rare.
Many grocery stores sell pre-packaged London broil. Look for one with even thickness. That helps it cook uniformly. If one end is thin and the other thick, it won’t cook evenly. You can pound it slightly to even it out, but that’s optional.
How To Cook A London Broil On The Grill
Now let’s break down the process step by step. Follow these instructions for a tender, juicy result every time.
Step 1: Choose The Right Cut
Pick a London broil that’s at least 1.5 inches thick. Thinner cuts cook too fast and get tough. Thicker cuts give you more room for error. Also, look for some marbling—small streaks of fat within the meat. It adds flavor and moisture.
If the meat is uneven, use a meat mallet to pound it to a uniform thickness. Place it between two sheets of plastic wrap and gently pound. Don’t overdo it; you just want even thickness.
Step 2: Season Generously
London broil benefits from bold seasoning. Because it’s lean, it needs flavor help. Start with salt and pepper. Use kosher salt and fresh ground black pepper. Apply them at least 40 minutes before grilling. This allows the salt to penetrate the meat, not just sit on the surface.
You can also use a dry rub. Try a mix of garlic powder, onion powder, smoked paprika, and a pinch of cayenne. Rub it all over the meat. Let it rest at room temperature for 30 minutes before grilling. Cold meat cooks unevenly.
Step 3: Preheat The Grill To High Heat
Your grill needs to be screaming hot. Aim for 500°F to 600°F. For a gas grill, turn all burners to high and close the lid for 10 minutes. For charcoal, light a full chimney of coals and spread them in a single layer. The coals should be glowing red with a light ash coating.
High heat sears the meat quickly, creating a crust while keeping the inside rare. Without high heat, the meat will steam and toughen.
Step 4: Oil The Grates
Use a pair of tongs and a paper towel dipped in vegetable oil. Rub the oil over the grates. This prevents sticking and helps with grill marks. Do this just before placing the meat on the grill.
Be careful—oil can flare up. Keep a spray bottle of water handy for small flames.
Step 5: Grill Over Direct Heat
Place the London broil directly over the hottest part of the grill. Leave the lid open if you want a more intense sear. Close the lid for even cooking. Cook for 4 to 5 minutes per side for medium-rare, depending on thickness.
Use a meat thermometer to check doneness. Insert it into the thickest part of the meat. For medium-rare, aim for 130°F to 135°F. For medium, 140°F to 145°F. Never go above 150°F—the meat will become tough.
Step 6: Rest The Meat
Resting is non-negotiable. Transfer the cooked London broil to a cutting board. Tent it loosely with aluminum foil. Let it rest for 5 to 10 minutes. During this time, the juices redistribute throughout the meat. If you cut too soon, all the juices run out onto the board.
Resting also allows the internal temperature to rise a few degrees. So if you pull it at 130°F, it will climb to about 135°F during rest.
Step 7: Slice Against The Grain
This step is crucial. London broil has long muscle fibers. If you slice with the grain, the meat will be chewy. Find the direction of the fibers—they look like lines running along the meat. Slice perpendicular to those lines. Cut thin slices, about 1/4 inch thick.
Angle your knife at 45 degrees for wider, more tender slices. This is called slicing on the bias. It shortens the fibers even more, making each bite easier to chew.
Tips For Perfect Grilled London Broil
Here are extra pointers to ensure success.
Use A Meat Thermometer
Don’t guess doneness by touch or time. A thermometer is your best friend. Insert it into the center of the meat. Digital instant-read thermometers are fast and accurate. They cost little and save you from ruined meat.
Marinate For Extra Tenderness
An acidic marinade can help break down tough fibers. Use ingredients like vinegar, citrus juice, or wine. Add oil, herbs, and spices. Marinate for 2 to 4 hours—no longer, or the meat can become mushy. Pat the meat dry before grilling to ensure a good sear.
Don’t Overcrowd The Grill
If you’re cooking multiple steaks, leave space between them. Overcrowding lowers the grill temperature and causes steaming. Cook in batches if needed. Keep the cooked meat warm in a low oven (200°F) while you finish the rest.
Let The Meat Come To Room Temperature
Take the London broil out of the fridge 30 to 60 minutes before grilling. This helps it cook more evenly. Cold meat in the center will be undercooked while the outside burns.
Common Mistakes To Avoid
Even experienced cooks make errors with London broil. Here are the most common ones.
Skipping The Rest
Cutting into the meat right off the grill is tempting. Don’t do it. You’ll lose all the juices. Resting is not optional—it’s essential.
Overcooking
London broil is lean and unforgiving. Medium-rare is the sweet spot. Anything beyond medium is dry and tough. Use a thermometer and pull it off the grill a few degrees early.
Cutting With The Grain
This mistake makes even perfectly cooked meat chewy. Always slice against the grain. Look at the fibers and cut perpendicular to them. If you’re unsure, make a small cut to see the direction.
Using Low Heat
Low heat will not sear the meat. It will slowly cook it, driving out moisture. You need high heat for a quick, hard sear. That’s the only way to get a crust while keeping the inside rare.
Serving Suggestions
Grilled London broil pairs well with simple sides. Try roasted potatoes, grilled vegetables, or a fresh green salad. A chimichurri sauce or compound butter adds richness. You can also slice it thin and serve on a bed of arugula with shaved Parmesan.
Leftovers are great in sandwiches or salads. Slice them thin and use within 3 days. Reheat gently in a skillet or microwave to avoid drying out.
Frequently Asked Questions
What is the best way to cook a London broil on the grill?
The best way is to use high heat, sear both sides quickly, and cook to medium-rare. Always rest and slice against the grain. This method gives you tender, juicy meat.
How long do you grill a London broil for medium-rare?
For a 1.5-inch thick London broil, grill 4 to 5 minutes per side over high heat. Use a thermometer to confirm an internal temperature of 130°F to 135°F. Times vary by thickness and grill heat.
Should I marinate London broil before grilling?
Marinating can add flavor and tenderness, but it’s not required. A simple salt and pepper rub works well. If you marinate, keep it to 2 to 4 hours to avoid mushy meat.
Why is my London broil tough?
Toughness usually comes from overcooking or slicing with the grain. Cook only to medium-rare and always slice against the grain. Also, let the meat rest before cutting.
Can I grill London broil from frozen?
It’s not recommended. Frozen meat cooks unevenly. Thaw it in the refrigerator overnight before grilling. For faster thawing, submerge the sealed package in cold water for an hour.
Final Thoughts
Grilling a London broil is simple once you know the steps. High heat, careful timing, and proper slicing make all the difference. Don’t skip the rest or the thermometer. With practice, you’ll get a perfect result every time.
Now you know how to cook a London broil on the grill. Fire up the grill, season your meat, and enjoy a delicious steak dinner. It’s a weeknight win that feels special.