1.5 kg (3 lb) piece of salmon, divided into 2 fillets
125 ml (4 fl oz) dry white wine
50 g (2 oz) butter
salt and pepper
Brush a large baking sheet with the oil, place half the onion, orange and lemon on top and scatter over some thyme sprigs. Place a salmon fillet, skin side down, on top of the fruit, onion and thyme. Put the remaining fruit, onion and thyme on the fish and season well, then place the remaining salmon fillet on top. Tie some kitchen string around the fish to secure.
Pour over the wine and dot the fish with the butter. Cook in a preheated oven, 220°C (425°F), Gas Mark 7, for 25 minutes or until just cooked through. Remove the fish to a serving plate.
Tip the juices and bottom layer of fruit into a sieve set over a bowl. Press any extra juice from the fruit and serve over the salmon with some crushed potatoes and beans.