Try to get thick fillets for this as they will have a juicer texture and bigger surface area to absorb the herb vinaigrette.
4tbsp olive oil
4 thick skin-on cod fillets
250ml chicken or vegetable stock
1 head of broccoli, broken into florets
12 Brussels sprouts, quartered
2 garlic cloves, crushed
100g fresh or vacuum-packed chestnuts, finely chopped
For the vinaigrette
¼ bunch of tarragon, leaves picked and finely sliced
¼ bunch of parsley, leaves picked and finely sliced 2tbsp capers, chopped
½ red onion, finely chopped 4tbsp white wine vinegar 150ml extra virgin olive oil
1 green chilli, deseeded and finely chopped
To make the vinaigrette, mix all the ingredients together in a bowl then set aside.
For the braised fish, heat 2 tablespoons of the olive oil in a non-stick frying pan over a high heat. Season the cod well with salt and pepper and carefully place in the pan, skin-side down. Cook for a couple of minutes until the base of the cod is nicely browned, then turn. Pour in 200ml of stock and cover the pan loosely with foil. Reduce the heat and simmer for a maximum of 5 minutes, until the cod is just cooked through. Heat the remaining olive oil in a wide frying pan over high heat until almost smoking. Add the broccoli and sprouts and fry until browned. Pour in the remaining 50ml of stock and add the crushed garlic, then reduce the heat slightly.
Cook for a few minutes until the vegetables are just tender and stir in the chestnuts.
To serve, divide the vegetables between plates and sit the cod on top. Drizzle generously with the vinaigrette and serve immediately.