Place the mirin, soy, miso paste, sesame oil, sugar and vinegar together into a saucepan, mix well, and then bring to the boil.
Turn down the heat and simmer the sauce until you have about 150mls.
Remove from the heat and cool.
Once cooled, pour half over the salmon and leave to marinate, best overnight in the fridge. But at a pinch 1 hour.
To cook the salmon, pre heat the grill to its hottest setting.
Lift out the salmon, leaving a little sauce on the fish, then place onto a grilling tray or dish.
Cook for 6-8 minutes, depending on the temperature of the grill, or until the salmon is JUST cooked, best left undercooked.
Meanwhile boil the rest of the marinade that is left, and serve with the salmon as a dipping sauce.
Serve the salmon with cooked fresh fettucine mixed with a little oil, butter and chopped fresh mint.