The first time that we tried cooking Korean bulgogi at home, we simply marinated the beef in a ready made imported sauce that we bought from the wholesale club.
It was not that bad but the flavor did not quite capture our expectation of bulgogi as we had tasted in Korean restaurants.
Just recently, I discovered an ingredient that Koreans use in making traditional bulgogi. You should not skip this important step when making the dish.
Aside from soy sauce, sugar, garlic, leeks, sesame oil, and black pepper, the beef is marinated overnight in Asian Pear that is grated. It can be purchased in some of the specialty groceries in the Philippines. If it is not available, any kind of pear will do.
"Despite having a texture similar to that of apples, Asian pears closely resemble other pear varieties..."
https://healthyeating.sfgate.com/benefits-asian-pears-4377.html
"Pear juice or puree is traditionally used in Korean meat marinades—the juice not only adds sweetness but also works to tenderize the meat. I've watched Korean friends and mothers use pineapple juice, apple juice, and even soda in lieu of pear juice, but I prefer the pear."
https://www.seriouseats.com/2011/03/asian-korean-barbecue-meat-marinades.html
I learned that pears or other types of fruit have an enzyme that helps to tenderize the meat.
"Marinades often differ slightly from establishment to establishment and home to home—a secret sauce of sorts—but generally include some combination of soy sauce, sugar, garlic, green onion, sesame oil and pear. The pear, often a juicy Asian variety, is especially critical. It contains an enzyme called calpain, which tenderizes the meat and adds a touch of sweetness."
https://www.smithsonianmag.com/arts-culture/brief-history-bulgogi-koreas-most-delicious-export-180968132/
"Many fruits such as kiwifruit, pineapple and papaya contain enzymes that have a tenderizing effect on meat. While it may not give you the same concentrated flavor that dry-aging will get you, fruit can be added to a marinade and it acts much faster. In the case of Bromelain, the enzyme found in pineapple, it’s so effective that it will turn your meat into mush if you let it marinate too long."
http://www.pbs.org/food/fresh-tastes/tenderizing-meat/
The marinated beef is then cooked with onions that give it an authentic flavor. It can also be grilled to perfection.
Korean bulgogi is very easy to make and is a staple in many Korean households.
