8-12 chicken thighs, boned and skin left on
80g white miso paste
40g root ginger, finely grated
4 tbsp mirin
6 tbsp cider vinegar
12 spring onions
1 tbsp sunflower oil
200ml white wine
6 tbsp water
Sea salt and freshly ground white pepper
125g walnuts, broken
80g unsalted butter
1½ tbsp maple syrup
250g small seedless red grapes
1 tbsp chopped tarragon
Place the chicken in a large bowl, stir together the miso paste, ginger, mirin and four tablespoons of the vinegar and pour the mixture over the chicken, cover with cling wrap and leave in the fridge to marinate for at least three hours. Overnight would be ideal.
Put the spring onions in a small saucepan and cover with water, bring to the boil and cook for five minutes, drain off the water, allow to cool and cut the spring onions in half lengthways.
Preheat the overhead grill to a high setting, place the chicken pieces on a baking tray, skin-side up, with all the marinade and grill for 10 minutes.
Heat a wok, add the spring onions and fry on a medium heat for four minutes, or until browned, pour in the remaining vinegar, reduce for a few seconds then pour in the wine, water, ½ teaspoon of salt and some white pepper and continue to cook for about six minutes.
Remove the chicken from the grill and add it to the pan along with the cooking juices.
Stir gently and bring everything to a low simmer, cover the pan and cook for 3-4 minutes, or until the chicken is just cooked through.
Remove the chicken from the pan and set it aside in a warm place.
Add the walnuts, butter, maple syrup and grapes to the pan and continue cooking, stirring until the butter emulsifies, for 2-3 minutes.
Serve the chicken with the sauce spooned on top and scatter over the tarragon.