Step 1Place the fernbrake in a large pot with enough water to cover and soak for 10 minutes. Place the pot on the stove and bring it to a boil. Boil, uncovered, for 30 minutes or until the fernbrake is tender. (It will turn a slightly lighter shade of brown.)
Step 2Drain the fernbrake, cool and vigorously squeeze out all of the remaining water. Cut off 2 inches of the woody ends. Then cut the remaining fernbrake into 2-inch-long pieces.
Step 3Transfer the fernbrake to a large bowl and season it with the soy sauce, minced garlic and black pepper, mixing thoroughly with your hands.
Step 4In a saute pan, heat the vegetable oil and saute the fernbrake over medium heat for 5 minutes. Remove from the heat, add the sliced green onions and cover. Let cool to room temperature. Transfer to a bowl and season with the sesame seeds, the red pepper powder and salt to taste.