Slice across the grain into 2 mm thick slices:
500 g beef flank steak
Place slices into a dish, and then add:
30 ml soy sauce (Korean, if available)
15 ml sesame oil
15 ml sesame seeds
1 ml pepper
40 ml green onion tops, sliced
25 ml sugar
15 ml rice vinegar
2 cloves garlic, minced
Cover and refrigerate for 12 to 24 hours. Remove from the refrigerator at least one hour prior to cooking. Remove the beef from the container, saving the marinade, and grill each piece for 30-45 seconds per side, until it is no longer pink. When you are arranging the beef on the grill, don’t let the pieces touch each other, or they will tend to stick together. Warm the marinade and serve the beef hot, over hot rice, with the marinade spooned over the rice.