1. In a small bowl, mix all the ingredients of marinade for beef. Cut the beef into julienne strips, along the grain. Marinate the beef for 20 minutes.
2. Cut the cucumber into 1½-inch (4-cm) long pieces, then cut it in half lengthwise. Remove the seeds. Cut the cucumber into 1/10-inch (0.2-cm) thick strips and marinade in brine for 10 minutes. Squeeze out the excess moisture.
3. Cut the onion into julienne strips.
4. Remove the stems of pyogo mushrooms and cut them into fine julienne strips.
5. Cut the carrot into 1½-inch (4-cm) long pieces, then cut into ½×1/10-inch (1×0.2-cm) strips.
6. Soak the sweet potato noodles in lukewarm water for 20 minutes.
7. Separate egg yolks and egg whites into two bowls and beat them well with a pinch of salt (How to make jidan garnishes).

1. Pan-fry the yolks and whites separately on a lightly greased skillet over low heat into very thin sheets. Cut into 1½×½-inch (4×1-cm) strips.
2. Heat the oil in a skillet and stir-frying separately in order, the onion, pyogo mushrooms and carrot, with a pinch of salt over high heat.
3. Heat a little oil in a skillet and stir-fry the marinated beef strips quickly, stirring to prevent them from sticking together.
4. Pour 4 cups of water into a medium pot and bring to a boil. Add the soaked sweet potato noodles and cook for 5 minutes. Turn off the heat and drain the noodles in a colander. Heat the oil in a skillet and stir-fry cooked noodles with the soy dressing for 5 minutes.
5. In a large bowl, put all the cooked vegetables, beef, noodles and toss to combine. Place them in a serving plate and garnish with fried egg pieces.

Serve at room temperature, but not too cold. When selecting the vegetables to use for japchae, consider the harmony of five colors: red, green, white, black and yellow. Use carrots or red peppers for red; cucumbers, spinach or squash for green; bellflower roots, bean sprouts or oyster mushrooms for white; pyogo mushrooms or black tree mushrooms for black; and julienned fried eggs ??for yellow.