marinate the steak by combining 2 tbsp olive oil, 2 tbsp soy sauce, 1 tbsp worcestershire sauce, 2 minced garlic cloves, 1 tsp black pepper, and optionally a squeeze of lemon juice in a bowl. place the steak in a resealable bag or shallow dish and pour the marinade over it. let it marinate in the refrigerator for at least 30 minutes; for maximum flavor, marinate for 2–3 hours (if in a hurry, 15 minutes will do).

cook the steak using your preferred method. for grilling, preheat the grill to high heat and cook the steak for about 4–5 minutes per side for medium-rare. for pan-searing, heat a cast-iron skillet until smoking, add a splash of oil, and cook the steak for approximately 4 minutes per side. after cooking, let the steak rest for 5–10 minutes to retain its juices.

while the steak rests, toast your bread by brushing each slice with olive oil or garlic-infused butter and toasting in the oven or on a hot griddle until golden and crispy.

to assemble the sandwich, spread your chosen condiment (mustard or horseradish) on one slice of toasted bread, add a layer of fresh greens, then lay on the thinly sliced steak. top with sautéed onions, mushrooms, and, if desired, a couple of slices of cheese. finish by drizzling a little extra olive oil or lemon juice over the steak, then place the other slice of bread on top and press down gently.