1 litre (35 fl oz/4 cups) water
10 g (¼ oz) kombu seaweed
10 g (¼ oz) katsuobushi (dried bonito flakes)
320 g (11¼ oz) dried udon noodles, or 4 packets pre-cooked udon
1 spring onion (scallion), finely chopped
Amani beef (beef simmered in a sweet sauce)
400 g (14 oz) beef, ideally a well-marbled cut, sliced
2 Tbs soy sauce
1 Tbs raw (demerara) sugar
2 Tbs mirin
200 ml (7 fl oz) dashi
1.2 litres (42 fl oz) dashi
3 Tbs mirin
3 Tbs soy sauce
1 tsp salt
2 Tbs sake
Soaking in water:
Place the water in a saucepan. Cut the kombu into 2 pieces and add to the water, then leave to soak for at least 30 minutes in the refrigerator. You can do this the night before or a few hours ahead of time.
Cooking the dashi:
Heat the water on a low heat until it just comes to a simmer, about 15 minutes. Don’t let it boil, or the seaweed flavour will be too strong.
Take out the kombu just before the stock comes to the boil and add the katsuobushi all at once.
Bring to the boil on a medium heat, then turn off the heat immediately. Let it infuse for 10 minutes.
Strain the dashi into a bowl. Let the dashi drip through, pressing lightly.
Udon and Soup:
For the beef, cut the beef slices into 3 cm (1¼ in) strips.
Place the beef, soy sauce, sugar and mirin in a saucepan. Sauté, stirring regularly, over a low to medium heat. Add the dashi and let it simmer on a low heat for 5 minutes.
To make the soup, put all the ingredients in a saucepan and bring to the boil.
Cook the noodles according to the instructions on the packet. Drain the noodles and divide between four bowls. Pour the soup over the noodles. Top with the beef, garnish with the spring onion and serve immediately.