Start by cooking the apples and sultanas in the butter with the spices for 5 minutes till soft. Meanwhile, place the cream, milk, sugar, vanilla extract into a large saucepan and bring almost to the boil. Take off the heat and stir in the cooked apple mixture followed by the couscous. Mix together well then pour into a greased 1 ½ litre ovenproof dish. Sprinkle over the extra sugar and the nutmeg and bake at 165`c for 30 minutes, or until beginning to turn golden. Remove from the oven and allow to sit for 15 minutes before serving.