Maeun Dwaejibulgogi (Spicy Pork Bulgogi)

You should have no issues substituting with beef. Do note that the recipe developers found that a slightly fattier cut of pork was right for this dish, so if you can, possibly use a cut of beef that has a bit of fat. Something like thinly sliced brisket or thinly sliced beef navel plate/beef belly can be found in Asian markets and these will do well.

Strangely, while they look alike and are both used in Korean cooking, perilla leaves are part of the mint family, and sesame leaves are part of the sesame plant. That said, perilla leaves are often sold in Asian markets labelled as sesame leaves. The best way to tell is to taste them: Perilla has a grassy, herbal taste with hints of anise or licorice while sesame leaves are slightly nutty and earthy in taste.

Pork cushion is a triangular, boneless, 2- to 3-pound roast cut from the anterior section of the picnic shoulder on the pig’s foreleg. It’s a well-exercised muscle and thus relatively lean (especially compared with pork butt, which sits just above it) and loaded with connective tissue—traits that make it more economical than pork butt and well suited to the low, slow, tenderizing heat of barbecue. It’s also a standard cut for pork bulgogi, for which it’s commonly sliced thin to shorten the muscle fibers, promoting tenderness, and to minimize the cooking time. Many Korean markets sell packages of presliced pork cushion for bulgogi, but skinless pork belly makes a good (albeit fattier) substitute. If you can’t find belly presliced, you can buy a slab and slice it yourself.