I got this recipe from an excellent book, Japanese Street Food by Emi Kazuko. In the book sardines are used but I used herrings instead as they were in season. The Japanese name for the recipe is Iwashi no Nanban-zuke and it is served as a starter or snack.
- Vegetable oil for deep frying
- 8 smallish herrings (get them cleaned, heads on)
- Plain flour (for dusting)
- Half an onion (thinly sliced)
For the nanban sauce:
- 100ml rice vinegar
- 5 tablespoons mirin (a sweet rice wine with low alcohol content)
- 1 teaspoon dashi granules (instant seaweed/fish stock, packet pictured right)
- 3 tablespoons sugar
- 2 tablespoons soya sauce
- half teaspoon salt
- 2 fresh bird's eye chillies (de-seeded and thinly sliced)
WARNING: Make sure your kitchen is well ventilated and that your housemate/partner doesn't mind the smell of fried fish lingering for a day or so!
Heat the oil for deep frying (I used a large wok). Dust the herrings with flour and deep fry 3 at a time in the hot oil for 2-3 mins each side (until golden). Remove and drain on kitchen towel.
Mix all the nanban sauce ingredients in a pan with 5 tablespoons of water and bring to the boil. Add the onion and remove form the heat. Pour into a large bowl (large enough for all the fish, I actually used a large tupper ware box).
Heat up the oil again and when hot return the herrings for 1 min each side. This gets the fish really crispy. Use a stop watch if you like, crucial not to fry for too long.
Remove from oil and put them into the nanban sauce straight away. When all fish are in spoon over sauce to make sure they all get coated. Let them cool then put on a lid and refrigerate for 1-2 days. Serve at room temperature.
A good place to buy Japanese ingredients in London is the Japan Centre near Piccadilly Circus. You can also buy online.