Finely chop onion, green onion, and pork.
Heat cooking oil in a pan and stir-fry the green onion to make green onion oil.
Add pork and stir-fry.
Add the onion and stir-fry until it becomes translucent.
Add black bean paste and sugar, then stir-fry together.
Add soy sauce and pepper, and mix well.
Pour in 100ml of water and bring to a boil.
Adjust the thickness with potato starch water.