Baked Mackerel with Fennel and Gooseberry Sauce

• 4 mackerel, cleaned and gutted, heads and backbones removed
• extra virgin olive oil
• salt
• freshly ground black pepper

Brush the fish with olive oil, season it and sprinkle it with cider. Place in an oiled ovenproof dish and bake in a preheated oven at 180°C / 350°F / Mark 4 for about 20 minutes. Meanwhile, make the sauce by cooking the gooseberries and fennel until soft