Chestnut mushrooms have a slightly nutty bite, which partners the spinach very well. During the autumn months, wild mushrooms make a wonderful alternative.
Preheat the oven to 200°C/400°F/gas 6. Dry the cod fillets, season with salt and pepper and lightly dust each in flour. Heat the olive oil in a non-stick ovenproof frying pan on top of the stove. Once hot, fry the fillets, skinned-side down, for several minutes until