Trim the bottom of the king oyster mushroom and slice it into thin pieces. Mix gochujang, red pepper powder, minced garlic, plum extract, and cooking wine to create the seasoning sauce.

Slice the green onion into small pieces.

Heat 2 tbsp of perilla oil in a pan and add the mushroom slices. Grill for 1 minute, flip, and grill for another 30 seconds.

Turn off the heat and add the seasoning sauce to the pan. Turn the heat back on and let it simmer briefly.

Add the grilled mushrooms to the sauce and mix quickly to coat them evenly.