Cut the pork neck slices and enoki mushrooms into bite-sized pieces.
Heat some cooking oil in a pan and stir-fry the pork neck slices.
When the pork is partially cooked, add the enoki mushrooms and stir-fry together.
Season with soy sauce, sugar, and black pepper.
Add onion and green onion, and stir-fry everything together.
Once everything is evenly cooked, serve on a plate.