If you’re wondering how long to cook a London broil in oven, you’ve come to the right place. The answer isn’t just one number, because it depends on how you like your beef and the size of your cut, but we’ll give you all the details you need for perfect results every time.
London broil is a fantastic, budget-friendly meal. It’s not actually a specific cut, but a cooking method for lean, tougher steaks like top round or flank. The secret is in a good marinade and proper slicing against the grain. When done right, it’s tender, flavorful, and a real crowd-pleaser.
This guide will walk you through everything. We’ll cover prep, cooking times, temperatures, and resting. You’ll learn how to avoid common mistakes and get that ideal juicy interior.
How Long To Cook A London Broil In Oven
For a standard 1.5 to 2-pound London broil, cook it in a 400°F (205°C) oven for about 15-20 minutes. This will get you to a nice medium-rare. You always need to use a meat thermometer for accuracy. Aim for 130-135°F (54-57°C) internally for medium-rare, then let it rest.
Remember, time varies. A thicker cut or a lower oven temperature means more time. A thinner piece or a hotter broil setting means less. The thermometer is your best friend here, not the clock alone.
Understanding London Broil: It’s a Method, Not a Cut
This is the most important thing to know. “London broil” refers to the way you cook and serve the meat, not the cut itself. Grocery stores often label top round or flank steak as London broil, which is fine. But you can use several lean cuts.
These cuts are from hard-working cow muscles. They have less fat, which means they can be tough if cooked wrong. The oven method we use, with high heat, helps to cook it quickly while keeping it tender. The real magic happens when you slice it thinly across the grain after cooking.
Essential Tools You’ll Need
- A reliable meat thermometer (instant-read is best).
- A sturdy baking sheet or roasting pan.
- An oven-safe wire rack (to lift the meat for even air flow).
- Sharp knife for slicing.
- Shallow dish for marinating.
Step 1: Choosing and Preparing Your Meat
Pick a cut that’s about 1.5 to 2 inches thick. Look for one with good color and some marbling if possible, though it will be lean. Flank steak and top round are the most common. Before anything else, pat the meat completely dry with paper towels. This helps with browning.
The Crucial Marinating Step
Marinating is non-negotiable for flavor and tenderness. An acidic component (like vinegar, citrus juice, or wine) helps break down tough fibers. Oil and herbs add flavor. You should marinate for at least 4 hours, but overnight is even better. Keep it in the fridge while marinating.
A simple marinade could be:
- 1/2 cup soy sauce
- 1/4 cup olive oil
- 2 tablespoons red wine vinegar
- 2 cloves garlic, minced
- 1 teaspoon black pepper
Step 2: Bringing to Room Temperature & Preheating
Take the meat out of the fridge about 30-45 minutes before cooking. Letting it come closer to room temperature promotes even cooking. If you put a cold steak in a hot oven, the outside can overcook before the inside is done.
While it sits, preheat your oven to 400°F (205°C). If you plan to use the broiler at the end, make sure your oven rack is positioned about 6 inches from the top element.
Step 3: The Cooking Process and Timing
Place your London broil on the wire rack set inside the baking sheet. This allows hot air to circulate all around. Season it simply with salt and pepper just before it goes in, even if it was marinated.
Detailed Oven Time Chart
These times are for a 1.5-2 lb cut in a 400°F oven. Always verify with a thermometer.
- Rare: 12-15 minutes, 120-125°F (49-52°C) internal.
- Medium-Rare: 15-20 minutes, 130-135°F (54-57°C) internal.
- Medium: 20-25 minutes, 140-145°F (60-63°C) internal.
- Medium-Well: 25-30 minutes, 150-155°F (66-68°C) internal.
We don’t recommend cooking London broil to well-done. It will likely become very tough and dry because of its low fat content. Medium-rare to medium is the sweet spot.
The Broiler Finish (Optional)
For a more charred, crusty exterior, you can finish the steak under the broiler for the last 2-3 minutes. Watch it closely to prevent burning. Some people prefer to start with a hot skillet on the stove to sear it, then transfer it to the oven. Both methods work well.
Step 4: The Most Important Step – Resting
When your meat thermometer hits 5 degrees below your target temperature, take the London broil out. The carryover cooking will bring it up the rest of the way. Place it on a clean cutting board and loosely tent it with foil.
Let it rest for a full 10 minutes. This allows the juices, which have been driven to the center by the heat, to redistribute throughout the meat. If you cut it immediately, all those flavorful juices will run out onto the board, leaving the meat dry.
Step 5: Slicing Against the Grain
Look closely at the meat. You’ll see lines of muscle fibers running in one direction; this is the “grain.” Using a very sharp knife, slice the meat perpendicular (at a 90-degree angle) to those lines. This cuts the long, tough fibers into short pieces, making each bite much more tender.
Slice it as thinly as you can, about 1/4-inch thick. This technique is what makes a London broil truly enjoyable to eat.
Common Mistakes to Avoid
- Skipping the marinade: You’ll miss out on flavor and tenderness.
- Not using a thermometer: Guessing leads to over or undercooking.
- Skipping the rest: This is a surefire way to get dry meat.
- Slicing with the grain: This makes the meat chewy and stringy.
- Using too low an oven temperature: It will cook too slowly and dry out.
Flavor Variations and Serving Ideas
Don’t be afraid to experiment with your marinade. Try balsamic vinegar and rosemary, or lime juice and cilantro for a different twist. A dry rub with coffee and chili powder can be amazing too.
London broil is incredibly versatile. Serve it sliced on its own with sides, or use it in other dishes:
- Slice it for sandwiches or salads.
- Add it to tacos or fajitas.
- Chop it for a hearty beef stroganoff.
- Serve with classic sides like mashed potatoes, roasted vegetables, or a crisp green salad.
Storing and Reheating Leftovers
Store leftover sliced beef in an airtight container in the fridge for up to 4 days. To reheat, avoid the microwave if you can—it makes it tough. Instead, gently warm slices in a skillet with a bit of broth or sauce over low heat until just warmed through. You can also eat it cold in sandwiches, which is delicious.
Frequently Asked Questions (FAQ)
What temperature should a London broil be cooked to?
For the best balance of tenderness and flavor, cook your London broil to an internal temperature of 130-135°F (medium-rare) or 140-145°F (medium). Use a meat thermometer inserted into the thickest part.
Can I cook London broil from frozen?
It’s not recommended. Cooking from frozen will result in uneven cooking—a overcooked outside and a cold inside. It also prevents proper marinating. Always thaw it completely in the refrigerator first for the best results.
How do you keep London broil from getting tough?
The three keys are: 1) Marinate it for several hours. 2) Do not overcook it; lean cuts get tough when well-done. 3) Always slice it thinly against the grain after a proper rest. Missing any of these steps can lead to a tougher texture.
What’s the difference between London broil and flank steak?
Flank steak is a specific cut of meat from the cow’s abdominal muscles. London broil is a cooking method that often uses flank steak, but can also use top round or other lean cuts. So, you can cook a flank steak using the London broil method.
Is it better to bake or broil a London broil?
Baking at a high heat (like 400°F) is more forgiving and promotes even cooking. Broiling uses very high direct heat from the top and requires close attention to prevent burning. A good compromise is to bake it most of the way, then finish under the broiler for 2-3 minutes for a nice crust.
How long should I cook a 3 pound London broil?
A 3-pound roast will take longer. At 400°F, start checking the temperature at around 30 minutes. It could take 35-45 minutes total to reach medium-rare, depending on it’s shape and your oven. The thermometer is essential for larger cuts.
Mastering how long to cook a London broil in the oven is a simple process once you know the steps. It all comes down to a good marinade, accurate temperature control, patient resting, and proper slicing. With this guide, you’re equipped to make a delicious, tender London broil that will impress at any dinner table. Remember, the investment in a good meat thermometer is worth every penny for this and many other kitchen projects.