Steak Sandwich Recipe

Make the marinade and marinate steak

In a shallow bowl or zip-top bag combine 2 tbsp olive oil, 2 tbsp soy sauce, 1 tbsp Worcestershire, 1 tbsp red wine vinegar, 2 minced garlic cloves, 1 tsp brown sugar, 1 tsp freshly ground black pepper and 1/2 tsp salt. Add the flank steak, press marinade around it, seal and refrigerate for at least 1 hour or up to 6 hours (longer will increase tenderness and flavor).

Bring steak to room temp

Remove steak from refrigerator 30 minutes before cooking to come to room temperature for more even cooking.

Cook steak

Heat a large cast-iron skillet or grill over high heat until very hot. Remove steak from marinade and pat dry with paper towels. Lightly oil the grill or skillet. Sear steak 3-4 minutes per side for medium-rare (internal temp ~130-135°F / 54-57°C) depending on thickness. Adjust time for desired doneness. Once cooked, transfer to a cutting board, tent loosely with foil and rest 8-10 minutes before slicing thinly against the grain.

Make a roux

In a small saucepan over medium heat melt 2 tbsp unsalted butter. Add 2 tbsp flour and whisk constantly for 1-2 minutes until the raw flour smell is gone and the roux is pale golden.

Finish the sauce

Gradually whisk in 1 cup whole milk, ensuring no lumps form. Bring to a gentle simmer and cook until slightly thickened, about 2-3 minutes. Lower heat to low and stir in 1.5 cups grated sharp cheddar, 1 tsp English mustard, 1/2 tsp Worcestershire, 1/4 tsp paprika, 1/4 tsp salt and 1/4 tsp black pepper. Stir until cheese melts and sauce is smooth. Keep warm on very low heat, stirring occasionally. If too thick, add up to 2 tbsp milk to loosen.

Slice vegetables

Peel and thinly slice 1 medium yellow onion. Core, seed and slice 1 red and 1 green bell pepper into 1/4-inch strips.

Sauté onions and peppers

Heat 1 tbsp olive oil in a skillet over medium-high heat. Add onions and peppers, season with 1/2 tsp salt and 1/4 tsp black pepper. Sauté, stirring occasionally, until softened and caramelized at the edges, about 8-10 minutes. Reduce heat if browning too quickly. Keep warm.

Make garlic aioli

In a small bowl combine 1/2 cup mayonnaise, 1 tsp lemon juice, 1 grated garlic clove, 1/4 tsp salt and a pinch of black pepper. Stir until smooth. Taste and adjust lemon or salt. Refrigerate until assembly.

Make pan jus

After cooking the steak, pour off excess fat from the skillet leaving brown bits. Place skillet over medium heat, add 1/4 cup red wine (optional) and scrape up browned bits with a wooden spoon. Pour in 1 cup beef stock and bring to a simmer. Add 1 tbsp butter for sheen. If you want a slightly thicker jus, mix 1 tsp cornstarch with 1 tbsp cold water, then whisk into the simmering jus and cook 1-2 minutes until slightly thickened. Season to taste with salt and pepper. Keep warm.

Prep potatoes

Wash and peel (optional) 2 large potatoes. Cut into 1/4- to 1/2-inch sticks for fries. Rinse in cold water until water runs clear to remove excess starch, then drain and pat dry thoroughly with kitchen towels.

Fry potatoes

Heat vegetable oil in a heavy pot or deep-fryer to 325°F (163°C). Fry potatoes in batches for 3-4 minutes until soft but not browned. Remove and drain on paper towels. Increase oil temperature to 375°F (190°C) and fry in batches again 2-3 minutes until golden and crisp. Drain on paper towels and immediately season with 1 tsp salt. Keep warm and crisp.

Toast baguette

Slice the baguette lengthwise to make sandwich rolls or into individual sandwich portions. Butter the cut sides lightly. Place on a hot skillet or under broiler for 1-2 minutes until lightly toasted and golden.

Slice steak

Slice the rested flank steak thinly against the grain into bite-size strips or slices appropriate for the sandwich.

Assemble sandwich

Spread a generous layer of garlic aioli on both toasted baguette halves. Pile a handful of arugula on the bottom half, add a layer of sliced steak, top with sautéed onions and peppers, then spoon warm Welsh rarebit cheese sauce over the steak and vegetables. Finish with a light drizzle of pan jus around the meat (not soaking the bread) for extra flavor. Close the sandwich and press lightly.

Plate and serve

Cut sandwich in half if desired, serve with a side of house cut fries. Offer extra jus and cheese sauce on the side. Serve immediately while hot.