Mince the pork and chop the vegetables.
In high heat, put oil in the pan and saute the pork with garlic and ginger until slightly toasted and fragrant.
Add the black bean paste and saute for a couple of minutes.
Add the onion and zucchini and saute again until slightly toasted and coated by the sauce.
Season with soy sauce, oyster sauce, and sugar. Mix this thoroughly.
Add water and bring it to a boil. Taste and adjust with more seasoning—soy sauce if it needs more salt or sugar if you like it sweeter.
Combine potato starch and water, then mix thoroughly. Gradually pour the slurry into the sauce and check until the desired consistency is reached.
In a separate pot, cook the noodles according to package instructions, then drain.
Wash noodles with cold water and let it drain for a few minutes.
Plate the noodles and top it with the jajang sauce. Garnish with cucumber or sunny side-up egg.
Serve with danmuji and kimchi and enjoy!