The 5-Minute London Broil Marinade That Actually Tenderizes
A good London broil starts way before the steak hits the hot pan. This simple 5-ingredient marinade breaks down the tough fibers so you get a tender, deeply savory cut of beef every time. It does the heavy lifting while you heat the grill or broiler, and the whole thing comes together in about 20 minutes of hands-on time.
Why This Marinade Works
What you taste first is the salty, tangy punch of soy sauce and balsamic vinegar. The acidity works on the meat right away, and the Worcestershire adds that dark, almost smoky depth. Oil rounds it all out so the steak chars instead of steaming.
You can marinate for as little as 30 minutes and still get noticeable tenderness. Give it a full 2 hours and the flavor soaks into every slice. The broiler or a cast-iron grill pan both give you a dark, crackly crust while the inside stays medium-rare.
Ingredients
- 1/3 cup soy sauce: regular strength, not low-sodium, for the best savory base
- 1/4 cup balsamic vinegar: adds tang and helps soften the meat
- 2 tbsp Worcestershire sauce: deep, beefy note that keeps the marinade from tasting flat
- 2 tbsp olive oil: keeps the meat from sticking and carries fat-soluble flavor
- 3 garlic cloves, minced: press or finely chop so it disperses evenly
- 1 tsp dried thyme (or oregano): rub it between your fingers to release the oils before adding
- 1/2 tsp freshly cracked black pepper: more than you think, the pre-ground stuff won’t cut through
- 1 1/2 to 2 lb top round or flank steak: the classic London broil cut, look for one about 1 inch thick
Variations / Substitutions
- Low-sodium soy sauce: use tamari for a gluten-free swap, but add a pinch of salt to the marinade so the flavor doesn’t soften
- Balsamic vinegar: red vinegar or fresh lemon juice both work, though the color will be lighter
- A touch of sweetness: stir in 1 tsp brown sugar or honey if you like a faint caramelized edge on the crust
- Herb switch: dried rosemary or a spoon of Dijon mustard changes the personality without extra work
- More heat: a pinch of red pepper flakes or a minced fresh chile in the marinade wakes up the whole dish
Crispy One-Pan Sausage and Potatoes Skillet is a perfect match if you’re wondering what to serve this marinade with.
How to Make London Broil Marinade
Step 1: Whisk Together the Marinade
Pour the 1/3 cup soy sauce, 1/4 cup balsamic vinegar, 2 tbsp Worcestershire, and 2 tbsp olive oil into a medium bowl. Add the minced garlic, dried thyme, and black pepper. Whisk until everything looks blended and a little frothy on the surface, about 15 seconds.
You can do this step up to a day ahead and keep the marinade in the fridge. Pull it out while you prep the steak so the oil isn’t cold and cloudy.
Step 2: Marinate the London Broil
Place the steak in a flat dish or a sturdy zip-top bag. Pour the marinade over the meat, turning it once to coat both sides. Press out as much air as you can if you’re using a bag, then seal it. Let it sit at room temperature for 30 to 60 minutes, or refrigerate for up to 2 hours. Anything past 4 hours and the vinegar can start to make the outer layer mushy.
When you pull the steak out, you’ll notice the surface has gone a shade darker and feels slightly tacky from the soy. That’s your cue it’s ready.
Step 3: Sear and Slice the Steak
Take the steak out of the marinade and pat it very dry with paper towels. The drier the outside, the better the crust. Discard the leftover marinade.
Get your broiler screaming hot or heat a heavy grill pan over high heat until you see a faint wisp of smoke. Lay the steak down and let it sear without moving it for about 4 to 5 minutes per side for medium-rare. The outside should be deeply browned with a few charred spots. Move the steak to a cutting board, tent it loosely with foil, and let it rest for 5 minutes. Slice it thin, always against the grain, and pile the pieces on a platter while they’re still warm and glistening.
A Few Notes Before You Start
- The single most common mistake is skipping the pat-dry step. If the steak is wet going into the pan, it stews instead of searing and you lose that dark crust.
- If your broiler has a high and low setting, use high and position the rack so the meat sits about 4 inches from the heat.
- The marinade does double duty if you set a spoonful aside before adding the raw meat and brush it on during the last minute of cooking.
- Thinner steaks, around 3/4 inch, will cook faster. The table below gets you close every time.
Steak thickness and approximate broil times for medium-rare:
| Thickness | Broil Time per Side | Target Doneness |
|---|---|---|
| 3/4 inch | 3 to 4 minutes | Medium-rare |
| 1 inch | 4 to 5 minutes | Medium-rare |
| 1 1/4 inch | 5 to 6 minutes | Medium-rare |
Storing Leftovers
- Refrigerate: cooked sliced steak keeps well for up to 3 days in a sealed container. The slices are best reheated gently so they don’t dry out.
- Reheating: a quick 30 to 40 seconds in a hot skillet with a tiny splash of water brings back the juiciness better than the microwave. You can also toss the cold slices into a salad.
- Serve cold: leftover London broil sliced thin is excellent on a sandwich with horseradish sauce and arugula.
What To Serve With London Broil
Roasted asparagus or green beans with a squeeze of lemon keep the plate bright and cut through the richness of the beef. Crispy parmesan roasted potatoes soak up any juices that escape the meat. If you want something cool, a simple cucumber and red onion salad in a light vinegar dressing balances the salty crust.
Frequently Asked Questions
Can I use this marinade on a different cut of beef?
Yes. It works especially well on flank steak, skirt steak, or even a tri-tip. The time stays about the same, but cook the meat to your preferred doneness.
How long is too long to marinate a London broil?
More than 4 hours starts to break down the surface too much. The meat will feel mealy instead of tender, even if the flavor is deep. Stick to 2 hours as the sweet spot.
Do I really have to pat the steak dry?
Yes. Skipping it is the fastest way to a gray, steamed exterior. The dry surface is what gives you the dark, crackly sear.
Can I grill this instead of broiling?
Absolutely. Prepare a grill for high direct heat and cook the steak about 4 to 5 minutes per side for a 1-inch cut. The char from the grates adds a great smoky layer.
London Broil Marinade Recipe
Ingredients
Method
- Whisk soy sauce, balsamic vinegar, Worcestershire sauce, olive oil, garlic, thyme, and pepper in a bowl until blended.
- Place steak in a dish or zip-top bag and pour marinade over it. Turn to coat, seal, and marinate at room temperature for 30 to 60 minutes.
- Remove steak from marinade, pat very dry, and discard marinade. Broil or grill over high heat for about 4 to 5 minutes per side for medium-rare. Rest 5 minutes, then slice thinly against the grain.
Notes
