Wash the beef thoroughly and blanch it in boiling water once.
Place the blanched beef and water in a pot, and simmer over low heat for a long time.
Remove the meat and shred it along the grain.
Return the meat and add minced garlic to the broth, then bring to a boil.
Dissolve perilla seed powder into the broth and stir while boiling.
Season with soy sauce for soup, salt, and pepper to taste.
Slice green onions and add them right before serving.