8 ounces flank steak, sliced against the grain into 1/4-inch thick slices
1 teaspoon oil
1 teaspoon soy sauce
1 tablespoon cornstarch, plus 1/4 cup
1/3 cup vegetable oil, for frying the beef
1/2 teaspoon minced ginger
5 dried red chili peppers (optional)
2 cloves garlic, chopped
1/4 cup low sodium soy sauce
1/4 cup water or low sodium chicken stock
2 tablespoons brown sugar
1 tablespoon cornstarch, mixed with 1 tablespoon water
2 scallions, cut into 1-inch long slices on the diagonal
Marinate the beef for 1 hour in 1 teaspoon oil, 1 teaspoon soy sauce, and 1 tablespoon cornstarch. Dredge the meat in the remaining 1/4 cup of cornstarch until lightly coated.
Heat 1/3 cup oil in the wok over high heat. Just before the oil starts to smoke, spread the flank steak pieces evenly in the wok, and let sear for 1 minute (depending upon the heat of your wok). Turn over and let the other side sear for another 30 seconds.
Remove to a sheet pan; tilt it slightly to let the oil drain to one side (lean it on a cookbook or cutting board). The beef should be seared with a crusty coating.
Drain the oil from the wok, leaving 1 tablespoon behind, and turn the heat to medium-high. Add the ginger and dried chili peppers, if using.
After about 15 seconds, add the garlic. Stir for another 10 seconds and add the soy sauce and chicken stock (or water). Bring the sauce to a simmer, add the brown sugar, and stir until dissolved.
Let the sauce simmer for about 2 minutes and slowly stir in the cornstarch slurry mixture–until the sauce coats the back of a spoon. Add the beef and scallions and toss everything for another 30 seconds.
There should be almost no liquid as the sauce should be clinging to the beef. If you still have sauce, increase the heat slightly and stir until thickened.