Line a sheet pan with paper towels.

Marinate the sliced flank steak for 1 hour in the 2 teaspoons of oil, 1 tablespoon of soy sauce, and 2 tablespoons of the cornstarch.

Dredge the meat in the remaining ½ cup of cornstarch until lightly coated.

Heat the 2 cups of vegetable oil in a medium-sized, heavy-bottomed pot over high heat.

Just before the oil starts to smoke (at 375-to-400 degrees Fahrenheit or 190-to-200 degrees Celsius), spread the flank steak pieces evenly in the pot, and let cook for 1 to 2 minutes, depending upon the heat of your oil. The cooked steak should be light golden-brown and crispy.

Remove the cooked steak to the sheet pan lined with paper towels to drain.