Remove the outer leaves of the cabbage and cut it into bite-sized pieces.

Drain the oil from the canned tuna using a strainer.

Mix gochujang, ketchup, corn syrup, and plum extract thoroughly to make the sauce.

Heat oil in a pan over high heat and stir-fry the cabbage until it becomes translucent. Set aside in a separate bowl.

Add the tuna and prepared sauce to the pan and stir-fry over medium-low heat. Add a small amount of water if the mixture is too thick.