Spicy cold buckwheat noodles

Instructions

1. To make the beef broth, combine all the ingredients in a large stockpot. Add 3 litres (101 fl oz/12 cups) water and bring to the boil over high heat. Skim off any impurities that rise to the surface, then reduce the heat to medium–low. Cover with a lid (leaving it slightly ajar), and simmer for 1 hour, until the beef is tender. Remove the beef from the stock and set aside to cool to room temperature. Wrap the beef in plastic wrap and chill in refrigerator for at least 4 hours, or preferably overnight.
2. Strain the broth through a fine-mesh sieve into a large airtight container. Reserve 60 ml (2 fl oz/¼ cup) of the broth to make the sauce. You can discard the rest of the broth or keep it to make
   Chilled buckwheat noodle soup
   .
3. To make the spicy sauce, combine all the ingredients in a food processor and blend to a fine purée. Refrigerate until needed.
4. Take the beef out of the refrigerator and slice it thinly against the grain.
5. Cook the noodles according to the packet instructions. Prepare an ice bath while the noodles are cooking. Once cooked, drain the noodles and immediately plunge them into the iced water to stop the cooking process. Drain, and place the noodles in a bowl.
6. Add the spicy sauce and toss until all the noodles are well coated. Divide the noodles among four serving bowls and top each with some pickled cucumber and radish, a few slices of beef and half a boiled egg. Sprinkle sesame seeds over the top and serve.