Miso, fermented soybean paste, is used in this dish to provide a beef and soy flavor that is terribly rich. Obviously it will stretch out the meat, but that does not seem to be the concern here. The Japanese have loved beef for the past 100 years or so, and they eat a great deal of it. Still, you will be surprised at how far this dish will go at a meal. Generally it is eaten with boiled rice.
1. Toast the sesame seeds in a frying pan. Cook only until a few pop and the rest turn golden brown. Grind with a mortar and pestle or run through a food blender. Do not grind too fine.
2. Add the miso to the sesame seeds and mix well. Add the soy sauce, sugar, optional MSG, and sake. Spread 'h of the mixture on a platter and place the beef slices in the marinade. Brush the remaining marinade on top.
3. Let stand for 30 minutes to 1 hour. Remove the beef from the marinade, scrape off the excess marinade, and reserve.
4. Broil, or pan-fry with a little oil. Heat the leftover marinade and serve with the beef.
