Here's what Korean people do:
1. Go to Asian market
2. Buy thin sliced beef for bulgogi (probably not available sliced this thin at your usual grocery store)
3. Buy bulgogi sauce (also not available at your usual grocery store)...
Marinate about an hour and cook (with mushrooms, onions, etc.) on the George Forman or similar grill. Serve with steamed “sweet” rice (probably not available at your usual grocery store) and homemade kimchee (probably not available at your usual grocery store…get the idea, here?)
No, I am not Korean, but have several friends that taught me to do it this way, and it ROCKS. Much better than trying to make the American version, IMHO.