Make Broth (Time: 0-4 hours + chilling): Simmer 1kg beef bones in 8 cups water 4 hours. Strain, chill until cold. Season with 1 tbsp salt, 1 tbsp sugar, 2 tbsp vinegar. Chill at least 2 hours.
Prepare Toppings (Time: 4 hours 0-10 minutes): Slice 1/2 Asian pear and 1/2 cucumber into thin matchsticks. Slice 1 boiled egg. Thinly slice 100g cooked beef.
Cook Noodles (Time: 4 hours 10-15 minutes): Cook 300g buckwheat naengmyeon noodles according to package (usually 3-4 minutes). Rinse under cold running water until completely cool.
Assemble (Time: 4 hours 15-20 minutes): Place noodles in bowls. Add ice cubes. Pour cold broth over. Arrange pear, cucumber, beef, and egg on top.
Serve (Time: 4 hours 20-25 minutes): Serve with mustard and vinegar on side. Mix before eating.









