This is from a Korean-American mom's blog, Eating and Living, a great source of Korean recipes. Traditionally some grated Asian pear is used to flavor and tenderize the meat, but a tart apple can be used instead. I added a sliced red bell pepper, which the recipe did not call for, but which worked together well. The pork must be very thinly sliced and I buy pork/pork belly sliced for bulgogi at the Korean market. Pork loin should have some fat on it. I used less soy sauce, but found the amount of gochujang to my taste.