Slice the king oyster mushrooms thickly.
Blanch the rice cakes briefly in boiling water.
Heat oil in a pan and stir-fry the king oyster mushrooms.
Add the rice cakes, onion, and green onion, and stir-fry together.
Add gochujang (Korean chili paste), soy sauce, minced garlic, chili powder, and water. Bring to a boil.
Simmer until all the ingredients are well combined.