PF Chang's Mongolian Beef Copy Cat Recipe. Tastes just as good as the restaurant!P.F. Chang's Mongolian Beef Copycat Recipe: (Recipe adapted from Food.com) 2 teaspoons vegetable oil ½ teaspoon ginger, minced 1 tablespoon garlic, chopped ½ cup soy sauce ½ cup water ¾ cup dark brown sugar vegetable oil , for frying (about 1 cup) 1 lb flank steak ¼ cup cornstarch 2 large green onions, chopped Directions: Sauce: Heat 2 tsp. of vegetable oil in a medium saucepan over medium/low heat. Don't get the oil too hot. Add ginger and garlic to the pan and quickly add the soy sauce and water before the garlic scorches. Dissolve the brown sugar in the sauce, then increase the heat to medium and boil the sauce for 2-3 minutes or until the sauce thickens. Remove it from the heat. Beef: Slice the flank steak against the grain into 1/4" thick bite-size slices. Tilt the blade of your knife at about a forty five degree angle to the top of the steak so that you get wider cuts. Dip the steak pieces into the cornstarch to apply a very thin dusting to both sides of each piece of beef. Let the beef sit for about 10 minutes so that the cornstarch sticks. As the beef sits, heat up one cup of oil in a wok (you may also use a skillet for this step as long as the beef will be mostly covered with oil). Heat the oil over medium heat until it's nice and hot, but not smoking. Add the beef to the oil and sauté until brown. Stir the meat around a little so that it cooks evenly. After a couple minutes, use a large slotted spoon to take the meat out and onto paper towels. Dab excess oil off meat with a paper towel and add to medium saucepan with the sauce in it. Put the pan back on the oven over medium/low heat. Add chopped green onions and let sauce simmer until warm. Serve over rice.