Cut the eggplant and thinly sliced pork belly into bite-sized pieces.
Slice the onion, green onion, and spicy chili pepper.
Heat cooking oil in a pan and stir-fry the green onion to bring out its aroma.
Add the pork belly and cook over medium heat.
Add the onion and eggplant, then stir-fry together.
Season with soy sauce, gochujang (Korean red chili paste), sugar, minced garlic, and black pepper.
Add the spicy chili pepper and stir-fry until all the ingredients are cooked evenly.