Bring a pot of water up to boil. Don't take the Soondae out the plastic package. Add it directly into the boiling water. Boil for 5 minutes. Then turn off the heat. Give it another 5 minutes to simply sit in the water and steam.
Carefully take the Soondae out of the package. Let it cool down. Then use a knife and cut into small bite-sized pieces. Sample one - it's ok to eat by itself and a dab of salt.
Prep Veggies & Make Sauce
Julienne your onion and carrot into thin slices. Then roughly dice the piece of cabbage. Roll-up the perilla leaves, tear off its stems and julienne into thin pieces.
Next, take out a mixing bowl and thoroughly mix: Gochugaru (2T), Gochujang (1T), Soy Sauce (2T), Sugar (1/2T), Honey (1T), Maesil (1T), Minced Garlic (1T), Sesame Oil (1T), Sesame Seeds (1T), Black Pepper (few shakes).
Make Soondae Bokkeum
Place frying pan on a medium-high heat. Once its hot, place in some oil. Then add in the cabbage, onions, and carrots. Stir-fry until the cabbage and onions turn soft. It should take about 4-5 minutes.
Once cabbage turns translucent and soft, add in the sundae. Then add in all of the spicy marinade sauce. And reduce your heat to a medium-low (!) Then stir-fry everything and get it nicely coated. After 1-2 minutes, turn off heat. Add on some of the sliced perilla leaves for color. You can also sprinkle-on some perilla seeds powder (if you have it). Give it one final stir and plate.
Garnish with the rest of the sliced perilla leaves on top. Bon Appetit!