Heat up 2 teaspoons of vegetable oil in a saucepan over medium heat, and cook and stir the garlic and ginger until they discharge their aroma, this should take about 30 seconds.
Pour in the soy sauce, hoisin sauce, water, and brown sugar. Raise the heat to medium-high, and stir for several minutes, until the sugar has dissolved and the sauce boils and slightly thickens. Remove from the heat, and set aside.
Slice your beef thin, this can be accomplished must easier by just doing two minor things; 1 have a super sharp knife and 2 semi freeze the meat so it is firm but not frozen. Makes cutting it so much easier.
Place the cornstarch into a glass bowl and add the beef, coating it thoroughly. Allow the beef and cornstarch to sit until most of the juices from the meat have been absorbed by the cornstarch, about 10 minutes.
Heat the vegetable oil in a deep-sided skillet I typically do this at medium high heat adjusting as I cook, as you add the meat the temperature of the oil goes down and need to be adjusted to keep the oil hot enough to cook the meat without making it greasy.
Shake excess cornstarch from the beef slices, and drop them into the hot oil, a few at a time. Stir briefly, and fry until the edges become crisp and start to brown, about 2 minutes for thicker slices, mine were fairly thin and cooked within a minute. Remove the beef from the oil with a large slotted spoon, and allow to drain on paper towels to remove excess oil. Make sure to move the beef as it drains so you don’t drain the next batch on the last batch of meat. That would defeat the purpose.
In a separate large sauté pan bring to medium heat. Add the beef slices to the pan, stir briefly, and pour in the reserved sauce. Stir once or twice to combine, and add the green onions. Bring the mixture to a boil, and cook until the onions have softened and turned bright green, about 2 minutes.
Serve over your predetermined choice of noodles or rice and garnish with the green chopped onion and sesame seeds.
