Slice the steak into bite size squares and
beat until very thin. Slice the scallions thinly and set aside. Using a
bowl, add the toasted sesame seeds, ginger, garlic, chili powder and soy
sauce, then combine with the meat and mix well into the seasonings. Heat
up a wok with the oil and stir-fry the seasoned meat and mushrooms on
high heat until meat is well cooked. Remove from wok and fry te
scallions, adding oil if necessary. Scatter the scallions over he meat
and serve hot with white steamed rice.