Chop the onion into coarse pieces.

Heat salad oil in a pan over medium heat, add pork, and cook until the color changes. Add onion and sauté until softened.

Add the Chapchae seasonings and bring to a boil. Cut harusame noodles into 3cm lengths using kitchen scissors and mix them in. Cover and simmer on low-medium heat for 5 minutes until the liquid reduces. Stir in the potato starch mixture to thicken.

Mix the dough ingredients in a bowl until combined. Knead until smooth and divide into 6 portions, rolling each into a ball.

Flatten each dough ball, place 1/6 of the Chapchae filling in the center, and wrap to form buns. Repeat for all portions.

Place the buns seam-side down in a pan, add 100cc water, and bring to a boil. Cover and steam over low-medium heat for 7 minutes. If water remains, cook over high heat to evaporate.