- Combine egg with bonito flake broth and seasoning in the saucepan. Boil until the sugar melts over medium heat.
- Heat olive oil and saute the mushrooms with medium heat.
- Heat the oiled square pan, pour in egg mixture. Place sauteed mushroom and cheese along the center. Slowly cook until the egg is set and fold to form a rectangle over low heat. Divide the egg roll into 6 equal portions, serve hot.