Cut the pork, onion, tofu, green onion, and potato into bite-sized pieces.
Add cooking oil to a pot and stir-fry the pork.
When the pork is cooked, add the onion, potato, and green onion and stir-fry together.
Add gochujang (Korean red chili paste) and red pepper powder, then mix well.
Pour in water and bring to a boil.
Add tofu and simmer for an additional 5–10 minutes.
Season to taste and top with green onion at the end to finish.