Cut the duck meat and vegetables into bite-sized pieces.
Heat cooking oil in a pan and stir-fry the duck meat.
When the duck is cooked, add glass noodles and vegetables, and stir-fry together.
Season with japchae sauce (soy sauce, sugar, sesame oil, etc.) to taste.
Once all ingredients are evenly cooked and flavored, turn off the heat.
Top the cup noodles with the japchae to finish.