London Broil Recipe

Season and rest

Pat the top round dry with paper towels. Rub with 2 tbs olive oil, then season evenly with 1.5 tsp kosher salt, 1 tsp black pepper, 1 tsp garlic powder and chopped rosemary if using. Let sit at room temperature for 30 minutes (or refrigerate up to overnight; bring to room temp 30 minutes before cooking).

Sear and roast

Preheat oven to 425°F (220°C). Heat a heavy oven-safe skillet over high heat until hot. Sear the roast 2–3 minutes per side until a deep brown crust forms. Transfer skillet to the preheated oven and roast until internal temperature reaches 125°F (52°C) for medium-rare or 135°F (57°C) for medium, about 12–18 minutes depending on thickness. Use a probe thermometer for accuracy.

Rest and slice

Remove roast to a cutting board and tent loosely with foil. Rest 10–15 minutes. Slice thinly across the grain into 1/8–1/4 inch slices for warm sandwiches.

While the roast rests (or concurrently), heat 1 tsp olive oil and 1 tbs butter in a skillet over medium heat. Add 2 cups thinly sliced onions and cook, stirring frequently, until softened and lightly caramelized, about 12–15 minutes.

Lower heat to medium-low, add 3 tbs balsamic vinegar and 1 tsp brown sugar. Stir to coat onions, cook another 3–5 minutes until vinegar reduces and onions are glossy. Season with 1/2 tsp kosher salt and 1/4 tsp black pepper. Keep warm until assembly.

Whisk together 1/2 cup mayonnaise, 2 tsp prepared horseradish, 1 tsp lemon juice, 1/2 tsp Dijon mustard and 1/2 tsp minced garlic in a small bowl. Season with 1/4 tsp salt and 1/8 tsp black pepper. Taste and adjust horseradish or lemon for brightness. Refrigerate until ready to use.

Warm a large skillet or griddle over medium heat. Lightly brush each naan with 1/2 tsp melted butter (use remaining 2 tsp total) and toast 1–2 minutes per side until golden and slightly crisp.

On each toasted naan, spread about 2 tbs horseradish aioli. Arrange a layer of warm sliced roast beef (about 4–5 oz per sandwich) across each naan, then top with a generous spoonful of balsamic onions. Place a slice of Swiss cheese over the onions and, if desired, return to the skillet covered for 30–60 seconds to melt the cheese, or broil briefly (watch closely).

If using, add a handful (~1/4 cup) of arugula or baby lettuce on top for freshness before finishing.

Sprinkle finished sandwiches with chopped parsley and a pinch (about 1/8–1/4 tsp) coarse sea salt. Slice each naan sandwich in half and serve warm with your choice of side (fries, salad, or chips).