Mongolian Beef (P.F. Changs Copycat)

Trim the fat and gristle off the top sirloin and slice it against the grain. Dip the steak pieces in the corn starch and let it sit for half an hour so it adheres to the meat. Meanwhile, heat 4 tsp of veg oil in a large saucepan over medium heat. Then add the ginger and garlic, stirring constantly for 1 minute. Quickly add the soy sauce and water before the garlic has time to burn. Dissolve the brown sugar in the sauce and raise the temperature to boiling for 2 - 3 minutes stirring constantly until the sauce is thickened. Remove from heat. After the beef has sat for 30 minutes, heat up 1 cup of oil in a large skillet or wok. Heat the oil over medium heat so it is nice and hot but not smoking. Saute the beef for 2 minutes or until it starts to brown slightly. It will keep cooking in the sauce. After a couple of minutes, use a slotted spoon to get the meat out and let it drain on a paper towel. Clean the oil out of the skillet and add the meat along with the reserved sauce. Simmer for 10 minutes then sprinkle with green onions and serve over hot rice.