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london broil recipe

Flank Steak London Broil with Caramelized Onions

Transform tough flank steak into a tender, flavorful London Broil with a garlic-lemon marinade and sweet caramelized onions, ready in just 10 minutes under the broiler.
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Prep Time 15 minutes
Cook Time 10 minutes
Total Time 25 minutes
Servings: 4 servings
Course: Dinner
Cuisine: American
Ingredients Equipment Method Notes

Ingredients
  

Main Ingredients
  • 1 lb beef flank steak best quality you can find
  • 2 onions medium, thinly sliced
  • 1 tablespoon butter
  • 2 tablespoon oil
  • 1 teaspoon lemon juice
  • 3/4 teaspoon salt divided: 1/4 for onions, 1/2 for marinade
  • 1/4 teaspoon pepper
  • 2 cloves garlic crushed

Equipment

  • Skillet
  • Oven with broiler
  • Cutting board
  • Chef's knife
  • Small bowl

Method
 

  1. Score both sides of the flank steak in a diamond pattern, cutting about 1/8 inch deep.
  2. Melt butter in a skillet over medium heat. Add sliced onions and 1/4 teaspoon salt. Cook until tender and caramelized, stirring occasionally. Keep warm.
  3. In a small bowl, whisk together oil, lemon juice, 1/2 teaspoon salt, pepper, and crushed garlic to make the marinade.
  4. Brush half of the marinade onto one side of the scored steak.
  5. Position oven rack 3 inches from the broiler. Broil the first side for 5 minutes.
  6. Flip the steak, brush with remaining marinade, and broil for another 5 minutes.
  7. Let the steak rest for a few minutes, then slice thinly against the grain.
  8. Serve slices topped with warm caramelized onions.

Notes

Score the flank steak deeply in a diamond pattern to tenderize it and allow the marinade to penetrate for maximum flavor.