Boil water in a pan. Cook beef meat until tender. Set aside, let it cool and cut diced. Keep the beef stock. While you can boil beef lung in separate pan. Cook until it tender. Set aside, let it cool and cut diced.
Add lime leaves, lemon grass and ginger into beef stock. Stir fry grounded ingredients until fragrant come out. Pour it into beef stock.
Add beef meat and beef lung diced into beef stock.
Cook for about 20 minutes.
Add salt, pepper and sugar to taste.
Serve soto with boiled egg. (you can add lime juice, sweet soy sauce and chilli if you like)