2 pounds flank steak
1/4 cup Worcestershire sauce
3 garlic cloves, chopped
Salt and freshly ground black pepper
Extra-virgin olive oil, for drizzling
4 plum tomatoes, sliced into thirds lengthwise
1 large red onion, sliced into 1/2-inch-thick disks
1 cup whole or reduced-fat sour cream
3 tablespoons prepared horseradish
1 heaping tablespoon Dijon mustard
1/4 cup fresh flat-leaf parsley leaves
1 bunch of arugula or watercress, cleaned and trimmed
Preheat a grill pan or outdoor grill on high.
Season the steak with 2 tablespoons of the Worcestershire, the garlic, salt, and pepper, drizzle with some EVOO, and marinate for 5 minutes.
Drizzle the tomatoes and red onion slices with a little EVOO, the remaining 2 tablespoons of Worcestershire, and some salt and pepper. Place on the grill and cook until well marked on both sides, 2 to 3 minutes. Remove from the grill and reserve.
Grill the flank steak for 6 to 7 minutes on each side. Remove the steak from the grill to a cutting board to rest for 5 minutes.
Split the baguette lengthwise without cutting it all the way through, then cut into 4 equal sub-style rolls. Drizzle EVOO over the inside and season with salt and pepper. Place the open-faced cut rolls on the grill, oiled insides exposed. Place a heavy pan atop the bread to keep it flat on the grill. Grill until well marked, 1 to 2 minutes.
In a bowl, combine the sour cream, horseradish, mustard, and parsley and season with salt and pepper.
Thinly slice the flank steak on an angle, cutting the meat against the grain.
To assemble the sandwiches, slather the inside of the grilled bread with the horseradish-Dijon cream. Divide the sliced steak, grilled red onions, and tomatoes among the 4 grilled baguette rolls. Pile some arugula or watercress on each sandwich and serve.
Some company came over to join me for this dinner since my husband went off for a men's game night. I think she really liked it. I went easy on the horseradish cream at first and wondered why it was so bland. I tried adding salt, but when I put more sauce on, it was just the right amount of flavor. It was perfect. I halved this recipe, so it was just enough for me to split with my daughters and for her to split with her 2-year-old son. I used spinach because I couldn't find any arugula or watercress this trip to the grocery store.