Soak glass noodles in hot water.
Slice vegetables (onion, carrot, green onion, shiitake mushrooms, etc.).
Add cooking oil to a pan and stir-fry the vegetables.
Add japchae sauce (soy sauce, sugar, sesame oil, pepper, etc.).
Add the soaked noodles to the pan and stir-fry together.
Heat cup noodle rice in the microwave.
Place the finished japchae on top of the rice and mix together.