Remove sleeve and using a sharp knife, cut film off. 10 to 15 minutes on a baking tray in the oven at about 160C – longer if you haven’t had the time to defrost it. If there is lots in the oven it may need longer. Cooking temperatures vary. and fancy ovens do things quicker, so check it from time to time. Food should have colour so bake it until it’s golden, bubbly and piping hot. Don’t microwave this dish – it wont be nice.