Step 1 Combine soy sauce, sesame oil and sugar. Marinate beef in mixture 30 minutes.
Step 2 Thread beef onto 2 parallel skewers (so that both skewers pierce meat), alternating with green onion pieces, rice cake pieces and mushrooms, if using.
Step 3Grill over high heat until meat reaches desired doneness, about 5 to 8 minutes for medium-rare.