Begin by preparing the dashi stock. Place the water, mushrooms and kombu in a large pan and place over a gentle heat. Bring up to 65℃ and, maintaining the temperature, leave to cook for 1 hour

Once cooked, strain the dashi through a fine sieve and measure out 360ml for the kamameshi. Place this in a pan with a tightly fitting lid and add the rice, sake, soy sauce, mirin, truffle and salt. Stir a little to combine and bring up to the boil, then cover with the lid and reduce the heat to low. Leave to simmer for 20 minutes, until the rice has absorbed all the water

Meanwhile, prepare the sansai kakiage. Place the vegetables and mitsuba leaves in a large mixing bowl and add the flour. Beat the egg in a separate container, then add to the mixing bowl along with the water. Stir through the vegetables until evenly coated and set aside

Place the oil in a wide, deep pan and heat up to 170℃. Once hot, pour the vegetables into the pan and fry until golden. Carefully turn the vegetables over and fry the other side for 1 minute, or until golden and crisp, then remove and leave to drain on kitchen towel

For the kakiage sauce, measure out 120ml dashi and add to a pan with the soy sauce and mirin. Mix together and heat, not allowing the mixture to boil, until warmed through

To serve, stir the rice well and divide between serving bowls. Cut the kakiage into four pieces and place these on top, pouring over a little of the kakiage sauce. Garnish with a pinch of sanshō pepper and serve immediately