Thoroughly mix all the ingredients except the sliced beef and half the sesame oil. Add the beef and let it sit in the marinade for an hour. Heat the remaining oil in a large frying pan. Put the pieces of beef in a few at a time and sear on both sides for about 1 minute per side.
2 tablespoons dark soy sauce 1 tablespoon light soy sauce 4 tablespoons sugar 1 bunch (about 8) scallions, white and tender green parts, coarsely chopped 1 2-inch piece fresh ginger, peeled and grated 2–6 cloves garlic, minced 2 tablespoons cooking rice wine 5 tablespoons sesame oil 2 pounds beef tenderloin, sliced as thin as possible