Dice pork, onion, potato, zucchini, and cabbage.
Heat some cooking oil in a pan and stir-fry the pork.
Add onion, potato, zucchini, and cabbage, and continue stir-frying.
Add black bean paste (chunjang) and stir-fry over low heat.
Add water and dissolved potato starch to make the sauce thick.
Pour the jjajang sauce over the noodles and mix well.