Slice the sundae into bite-sized pieces. Cut the cabbage, onion, carrot, and green onion into thick pieces. Thinly slice the perilla leaves for garnish.

Mix gochujang, chili powder, soy sauce, mirin, oligosaccharide, sugar, minced garlic, sesame oil, and black pepper to make the seasoning sauce.

Heat oil in a pan and stir-fry the green onion until fragrant.

Add the cabbage, carrot, and onion to the pan and stir-fry until softened.

Add the sundae and stir-fry until combined with the vegetables.

Pour the seasoning sauce into the pan, then add the perilla leaves and chilies. Stir-fry until everything is well coated.

Add 2 tbsp of perilla seed powder and mix well. Adjust the amount to your taste.

Turn off the heat and transfer the stir-fry to a serving plate.