Cut onions, pork, potatoes, and cabbage into bite-sized pieces.
Add cooking oil to a pan and stir-fry the pork.
When the pork is cooked, add onions, potatoes, and cabbage, and stir-fry together.
When the vegetables are mostly cooked, add black bean paste and stir-fry.
Add water and potato starch, then simmer until thickened.
Season with salt and pepper to taste.
Pour the sauce over boiled Chinese noodles to finish.