London Broil Recipe

inspired by

@winstonsgrille

Aug 28 2025

•

1h 30m

•

Serves 4

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Recipe information

Make London Broil in just 1h 30m. Marinated flank steak, grilled to order, topped with mushroom demi-glace, served with homemade mashed potatoes and sautéed vegetables

Marinating the Steak

1. Prepare the Marinade

In a bowl, combine soy sauce, olive oil, minced garlic, black pepper, oregano, and thyme. Mix well.

2. Marinate the Steak

Place the flank steak in a resealable bag or shallow dish. Pour the marinade over the steak, ensuring it is well coated. Seal or cover and refrigerate for at least 2 hours, preferably overnight.

Cooking the Steak

3. Preheat the Grill

Preheat the grill to medium-high heat.

4. Grill the Steak

Remove the steak from the marinade and discard the marinade. Grill the steak for about 5-7 minutes per side, or until desired doneness is reached. Let it rest for 5 minutes before slicing.

Making the Mushroom Demi-Glace

5. Sauté the Mushrooms

In a saucepan, melt butter over medium heat. Add sliced mushrooms and sauté until tender.

6. Prepare the Sauce

Add beef broth and red wine to the pan. Bring to a boil, then reduce heat and simmer for about 15 minutes.

7. Thicken the Sauce

In a small bowl, mix cornstarch with water to create a slurry. Stir this into the sauce and cook until thickened.

Making the Mashed Potatoes

8. Cook the Potatoes

In a large pot, boil diced potatoes until tender, about 15-20 minutes. Drain and return to pot.

9. Mash the Potatoes

Add butter and milk to the potatoes. Mash until smooth and creamy. Season with salt and black pepper to taste.

Sautéing the Vegetables

10. Prepare the Vegetables

In a skillet, heat olive oil over medium heat. Add bell peppers, zucchini, and carrots.

11. Sauté the Vegetables

Cook for about 5-7 minutes, stirring occasionally, until the vegetables are tender. Season with salt and black pepper to taste.

Serving

12. Plate the Dish

Slice the grilled flank steak and serve topped with mushroom demi-glace. Serve with a side of mashed potatoes and sautéed vegetables.