Cut the beef brisket and enoki mushrooms into bite-sized pieces.
Slice the onion and scallion thinly.
Heat oil in a pan and stir-fry the scallion to make scallion oil.
Add the beef brisket and stir-fry. Once the beef loses its redness, add the onion and enoki mushrooms.
Add gochujang (Korean chili paste), chili powder, minced garlic, soy sauce, black pepper, and other seasonings, then stir-fry quickly over high heat.
Add rice cakes (tteok) and a bit of water, stir-frying until done in a tteokbokki style.