Remove the bream from the fridge to allow it to come to room temperature
Place the dashi stock, sake and soy sauce in a large lidded saucepan or, ideally a large Japanese claypot, then stir in the rice, ginger and bonito flakes
Slice the mushrooms into thin strips and add them to the pan. Carefully place the bream fillets on top, skin-side up. Place the lid on the pot and cook over a medium heat for 14 minutes
After 14 minutes, turn off the heat and leave for a further 12 minutes. Do not remove the lid or stir the pot
After this time, add the mizuna leaves then replace the lid for 20 seconds to infuse
Lift the lid off the pot and give the contents a stir, naturally breaking up the fish into bite-sized pieces
Leave the pot with the lid off for 30 seconds to cool a little, then divide between bowls and finish with kimone leaves (if using) and a little yuzu juice and zest, to taste