Wash the youngchae and eggplant thoroughly and cut them into bite-sized pieces.
Finely chop the onion and garlic.
Heat cooking oil in a pan and stir-fry the garlic and onion.
Add the eggplant and stir-fry, then add the youngchae and stir-fry together.
Season with soy sauce, sugar, and pepper.
Serve the stir-fried ingredients over rice to finish.