Blanch beef in boiling water then drain. In a clean pot, add beef, water, spices and seasonings. Bring water to a boil then leave to simmer for 1-1.5 hours.
When completely cool, place beef and broth (discard spring onion, ginger, spices and the fat floating on the surface if there is any) in separate containers. Store in the fridge for at least 1 hour (see note 1).
Cook soba noodles according to the instructions on the package. Drain and rinse under running water to cool fully.
Meanwhile boil egg. Peel and halve it.
Pour cooled broth into two large serving bowls. Add vinegar, sugar and salt. Cut the beef into thin slices (see note 2).
Place the noodles into two bowls. Top with beef, egg, apple, cucumber, kimchi and red chilli paste. Sprinkle sesame seeds over.
1. The beef chunks need to be cooled in the fridge before slicing (otherwise it falls apart easily). If you’d like the broth even cooler, place it in the freezer for a short while until ice fragments begin to form.2. You are likely to have leftover beef slices, keep them in the fridge for the next meal. They taste delicious with just a little homemade chilli oil.
Cold soba noodles in beef broth (延吉冷面) by Red House Spice