From Alicia Maher’s cookbook, Delicious El Salvador, this recipe is bursting with delicious flavors and makes for a hearty, scrumptious dinner!
Trim any excess fat from the edges and pound the steaks with a meat mallet, to about 1/4-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.
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.
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.
Top the steaks immediately with the onions and pan juices, then garnish before serving with the sliced tomatoes and greens of your choice.