Such a tiny fish, but …
It has to be cooked, but not too much, has to be eaten entirely and express full variation of its being, has to be crispy only to the head, its liver clots to the near degrees to diffuse its sweet bitterness, but does not explode, the tail must be slightly dried, but not its back, bring out humidity from its body but not too much, the point is to enclose it under 1mm of very cooked flesh but control the inertia of the heat, such an art for a 15 grams fish.
After many, many attempt, here is the way:
Soak the little animals for 1 hour in a mixture of fermented mushroom water and cucumber juice
Sponge them well
Skewer in order to give a nice shape in motion, without piercing the liver
Dry for 12 hours in the fridge
Let the Ayu rise for 30 minutes in temperature
Using a resistance heat gun, apply the hot air at 170°C , stay at 2 cm from the target as follows:
30 seconds on the top of the head, 15 seconds under the jaw, pass in fastly back and forth 5 seconds on the dorsal spine.
Bake at 150°C, low ventilation for 7 minutes
Remove from oven and let stands for 10 minutes
Bake again for 3 minutes at 125°C
Leave to rest for 5 minutes
Remove slowly and delicately the Ayu from peaks
Just before serving, spray cucumber water on the fish
Bake 1min45 to 240oC