Here is a recipe for Miso black cod:
4 x 200g thick black cod fillet, skin on
Vegetable oil, for greasing
2 limes, quartered
For the marinade:
4tbsp white miso paste
2 garlic cloves, finely grated
10g fresh root ginger, peeled and finely grated
2tbsp caster sugar
1tbsp seasoned rice vinegar
Put all the marinade ingredients in a plastic or glass bowl - it must be non-metallic - and mix well.
Add the fish, cover the bowl with cling film and leave in the fridge for at least two hours preferably overnight.
Preheat the oven to 180C/Fan 160C/Gas 4. Lightly oil a non-stick tray, put fish, skin side down, on it. Spoon two tablespoons of marinade over the fish and bake for 10 to 12 minutes in the oven.
Remove the fish from the oven, spoon over remaining marinade and put the tray under grill until golden brown.