Even though it takes more time and effort, the best way to tenderize is with a mallet or with the dull side of the knife blade. People may use coke, kiwi, pear, pineapple etc. etc. to tenderize meat, but truly the best Kalbi is physically tenderized rather than via acid. This is also how I mash my garlic, but a food processor works well too. Chop 1 small onion - using a food processor is best because you want a really soft mashy consistency. 2 cup soy sauce, aprox.
All measurements are approximations.
Sometimes I will use honey or maple syrup in lieu of sugar. If there is not enough liquid mixture, make more and add it to the meat. When ready to grill the meat, chop green onions or chives and add to the mixture. Grill till meat is well done. I prefer to grill meat on a gas BBQ or even grill in the oven, but you can also fry it in a pan.