London Broil Recipe Oven: Marinated Flank Steak With Caramelized Crust

This oven-baked London broil delivers restaurant-quality results with a caramelized crust and juicy interior. I developed this method after years of trial and error, focusing on a simple marinade that tenderizes the flank steak while enhancing its natural beef flavor.

The key is a high-heat oven that mimics grilling, creating that signature browned exterior without drying out the meat. A quick sear in a hot pan before roasting ensures maximum flavor development and a beautiful crust.

What you get is perfectly cooked steak with a rich, beefy taste and a slightly crisp exterior. The marinade penetrates deeply, making every bite tender and flavorful, while the oven method guarantees consistent results.

Serve sliced thinly against the grain with your favorite sides. This technique works every time.

Ingredients for London Broil Recipe Oven

Flank steak plus a bold marinade. Oven does the rest for that perfect crust.

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The steak is everything here. Flank steak labeled as London broil at the grocery store is ideal—look for good marbling and a rich red color. Whole Foods or Costco have great options, but any supermarket should carry it. Aim for 1-1.5 inches thick; anything thinner dries out too fast. If you see top round labeled as London broil, grab that—it works too.

No flank steak? Top round or sirloin tip are solid substitutes (just slice thin). Swap soy sauce for tamari for gluten-free. Out of Worcestershire? Extra soy sauce plus a dash of fish sauce (if you have it) mimics the depth. The herbs can be dried at one-third the amount. Brown sugar missing? White sugar plus a splash of molasses gets you close.

Marinate overnight for maximum tenderness (but even 2 hours works in a pinch). Keeps in the fridge for 3-4 days raw, or freeze the marinated steak for up to 3 months. Leftovers? Slice thin and toss into stir-fries or tacos.

Step-by-Step Instructions for Marinated Flank Steak With Caramelized Crust

This method guarantees a perfectly caramelized crust and tender, juicy meat every time.

Step 1: Create the Flavor-Packed Marinade

In a large bowl, whisk together the 0.5 cup Soy Sauce, 0.25 cup Olive Oil, 2 tbsp Worcestershire Sauce, 1.5 tbsp Dijon Mustard, 2 tbsp Brown Sugar, and 2 tbsp Balsamic Vinegar until the sugar dissolves completely. The balsamic adds a subtle tang that balances the richness.

Add the 4 cloves Garlic Cloves (minced), 1 tsp Black Pepper, 1 tsp Kosher Salt, 0.5 tsp Red Pepper Flakes, 1 tbsp Fresh Rosemary, and 1 tbsp Fresh Thyme. Stir to combine—this aromatic blend infuses the flank steak with layers of flavor during marinating.

Step 2: Marinate the Flank Steak for Maximum Tenderness

Place the 2 lb Flank Steak in a resealable plastic bag or shallow dish and pour the marinade over it, ensuring the steak is fully coated. I like to massage the marinade into the meat to help it penetrate deeper.

Seal the bag or cover the dish and refrigerate for at least 4 hours, but overnight is ideal. The longer it marinates, the more tender and flavorful the steak becomes. Flip the steak halfway through marinating to ensure even exposure to the marinade.

Step 3: Sear and Oven-Finish for a Perfect Crust

Preheat your oven to 400°F. Remove the steak from the marinade (reserve the marinade) and pat it dry with paper towels—this is crucial for achieving a good sear. Heat an oven-safe skillet over high heat until very hot, about 2 minutes.

Add the steak and sear for 3-4 minutes per side until a deep, caramelized crust forms. You’ll see the edges turn dark brown and smell that rich, savory aroma. Transfer the skillet to the preheated oven.

Step 4: Roast to Desired Doneness

Roast the steak in the oven for 8-10 minutes for medium-rare, or until an instant-read thermometer inserted into the thickest part registers 130-135°F. For medium, aim for 140-145°F and add 2-3 minutes of roasting time.

The marinade sugars will caramelize further, creating a glossy, flavorful crust. Avoid overcooking—flank steak is best when it’s still slightly pink in the center for maximum tenderness.

Step 5: Rest, Slice, and Serve

Transfer the steak to a cutting board and tent loosely with foil. Let it rest for 10 minutes—this allows the juices to redistribute, ensuring every slice is moist and flavorful. Slicing too soon will cause the juices to spill out, leaving the meat dry.

Slice the steak thinly against the grain into ¼-inch thick strips. The grain runs lengthwise in flank steak, so cutting across it shortens the muscle fibers, making each bite more tender. Serve immediately with the reserved marinade reduced as a sauce if desired.

Health Benefits of This Dish

Protein Powerhouse

This dish delivers a serious protein punch—about 50 grams per 6-ounce serving—supporting muscle repair and keeping you full for hours. Flank steak is a lean cut that still packs rich beefy flavor without excessive saturated fat. 💪

Iron and Zinc Boost

Beef is one of the best sources of heme iron, which your body absorbs more easily than plant-based iron. A serving provides about 20% of your daily iron needs plus 30% of daily zinc, crucial for immune function.

B Vitamin Complex

You’ll get a full spectrum of B vitamins, including B12 for energy metabolism and B6 for brain health. Flank steak is particularly rich in these nutrients, which help convert food into usable energy.

Low-Calorie Option

At around 200 calories per 4-ounce serving before marinade, this is a relatively low-calorie protein choice. The marinade adds minimal calories while maximizing flavor and tenderness.

Rich in Selenium

Beef provides selenium, a powerful antioxidant that protects cells from damage. This cut offers about 40% of your daily selenium needs in a single serving, supporting thyroid health and immunity.

I love that this meal satisfies both my taste buds and my nutritional goals. 🥩

Frequently Asked Questions