Oven Cook from Chilled: Before Cooking: Preheat oven 190°C/ Fan 170°C/ Gas 5. Remove all packaging. Place the ribs on a baking tray and add 100 ml of water to the bottom of the tray. Cover the tray tightly with foil and place it on the middle shelf of the oven. During Cooking: After 70 minutes, remove the foil and then cook for a further 20 minutes. After cooking, check that the food is piping hot throughout, all juices run clear, and no pink colour remains. This is only a guide. All cooking appliances vary.