- 400 g / 14 oz dried soba noodles
- 1 spring onion (scallion), sliced
- shichimi togarashi (optional)
For the tempura
- 16 medium raw tiger or king prawns (jumbo shrimp), heads and shell removed, tails intact
- 400 ml / 14 fl oz / 1 ⅔ cups ice-cold water
- 1 large (US extra large) egg, beaten
- 200 g / 7 oz / scant 2 cups plain (all-purpose) flour
- vegetable oil, for deep-frying
For the soup
- 150 ml / ¼ pint / ⅔ cup mirin
- 150 ml / ¼ pint / ⅔ cup shoyu
- 900 ml / 1½ pints / 3¾ cups water
- 25 g / 1 oz kezuri-bushi or 2 x 15 g / ½ oz packets
- 15 ml / 1 tbsp caster (superfine) sugar
- 5 ml / 1 tsp salt
- 900 ml / 1½ pints / 3¾ cups dashi stock or the same amount of water and 12.5 ml / 2½ tsp dashi-no-moto
- To make the soup, put the mirin in a large pan. Bring to the boil, then add the rest of the soup ingredients apart from the dashi stock. Bring back to the boil, then reduce the heat to low. Skim off the scum and cook for 2 minutes. Strain the soup and put back into a clean pan with the dashi stock.
- Remove the vein from the prawns, then make 5 shallow cuts into each prawn's belly. Clip the tip of the tail with scissors ad squeeze out any moisture from the tail.
- To make the batter, pour the ice-cold water into a bowl and mix in the beaten egg. Sift in the flour and stir briefly; it should remain fairly lumpy.
- Heat the oil in a wok or deep-fryer to 180C / 350F. Hold the tail of a prawn, dunk it in the batter, then plunge it into the hot oil. Deep-fry two prawns ant a time until crisp and golden. Drain on kitchen paper and keep warm.
- Put the noodles in a large pan with at least 2 litres / 3½ pints / 9 cups rapidly boiling water, and stir frequently to stop them sticking.
- When the water foams, pour in about 50 ml / 2 fl oz / ¼ cup cold water to lower the temperature. Repeat when the water foams once again. The noodles should be slightly softer than al dente pasta. Tip the noodles into a sieve and wash under cold water with your hands to rinse off any oil.
- Heat the soup. Warm the noodles with hot water, and divide among individual serving bowls. Place the prawns attractively on the noodles and add the soup. Sprinkle with sliced spring onion and some shichimi togarashi, if you like, then serve immediately.