Fillet of Sea Bass with Citrus Sauce

Preheat the oven to 220C/gas 7. Cut out two large pieces of foil about 15" square. Leave the skin on the fish and rub it generously with olive oil to soften and flavour the skin. Cut each fillet in half, and season the underside of the fish. Chop the spring onions and spread them thickly on the foil, then place the pieces of fish on top, skin side uppermost. Seal down three sides of the foil. Pour the wine, juice of 1/2 lemon and the juice of one tangerine into each packet, then add a little tangerine peel and seal the remaining side. Bake in the oven for about 4-5 minutes until the foil puffs up (this tells you that the fish is cooked). Squeeze the remaining fruit juices into a wide shallow pan, and add a teaspoon of finely- shredded tangerine zest, the sugar and seasoning. Chop the butter into small pieces. Open the fish packets at one end and pour the fish cooking liquor into the pan. Bring the juices and liquor to the boil and reduce by half to concentrate the flavour. Whisk in the butter a little at a time until the sauce is thickened and glossy. Remove the fish from the foil and serve it on the spring onions with sauce poured around.