Cut the beef brisket into bite-sized pieces.
Slice the onion, green onion, spicy chili, napa cabbage, and carrot into bite-sized pieces.
Heat some cooking oil in a pan, add green onion, and stir-fry to make scallion oil.
Add the beef brisket and stir-fry.
Add onion, napa cabbage, carrot, spicy chili, and garlic. Stir-fry together.
Add chili oil and red pepper powder, then mix well.
Pour in water and bring to a boil.
Season with oyster sauce, soy sauce, salt, and pepper.
Place rice in a bowl, pour the boiling jjamppong broth over it, and serve.