2poundstop sirloin steak (or any other tender cut you prefer),sliced into 6 equal portions
1teaspoonsalt
¼teaspoonfreshly ground black pepper
½cup yellow mustard
1cuponion,thickly sliced (rings, ½-inch-thick)
3tablespoonsvegetable oil
4tablespoons Worcestershire sauce
Garnish
2 to 3largetomatoes (firm but ripe),cut into about 12 slices (¼-inch-thick)
6leavesescarole or butter lettuce; or sprigs of watercress
Instructions
Prep steak and marinate. Trim any excess fat from the edges and pound the steaks with a meat mallet, to about ¼ inch thick. Season with he salt and pepper, rub with the mustard, place in a shallow dish, and add the sliced onions on top. Cover and marinate in the refrigerator for a couple of hours.
Sauté steak. In a large skillet, heat the oil over a high flame until it's almost smoking. Season the steaks with the salt and pepper, and add them to the skillet. Cook on each side for about 1 minute, turning once, until golden brown. Remove the meat from the skillet and set aside in a serving dish.
Sauteé onions. Reduce the flame to medium high, and in the same skillet with the oil remaining from cooking the steaks, fry the onions until golden, 8 to 10 minutes. Reducing the flame to low, add the Worcestershire sauce and cook the onions for about another 20 seconds. Remove skillet from the stove.
Assemble and serve. Top the steaks immediately with the onions and pan juices, then garnish before serving with the sliced tomatoes and greens of your choice.