300 g (10 oz) skinless cod fillets, cut into chunks
150 g (5 oz) raw peeled large prawns
750 g (1 1/2 lb) potatoes, peeled and cut into chunks
2 spring onions, sliced
salt and pepper
Heat 1 tablespoon of the oil in a saucepan. Add the fennel and garlic and cook for 5–7 minutes until softened. Add the tomatoes and tomato purée and cook for a further 2 minutes until softened. Pour over the wine and cook until nearly boiled away, then add the measurement water and fish. Cook for 3 minutes. Add the prawns and cook for 3–5 minutes until just cooked through.
Meanwhile, cook the potatoes in a saucepan of salted boiling water for 12–15 minutes until soft. Drain and mash with the remaining oil, the spring onions and a little water to loosen. Season well with salt and pepper.
Arrange the fish and sauce in a baking dish. Spoon over the mash. Cook under a preheated hot grill for 3 minutes until browned. Serve immediately.