In a saucepan combine rice, milk, salt and 1 tablespoon sugar. Bring to the boil, reduce the heat to low, cover and simmer for about 15 minutes until rice is soft.
Preheat oven to 200 C / Gas 6.
Add vanilla, egg and remaining sugar to the rice and mix well.
In a small bowl mix apple slices with cinnamon. Grease a baking dish and place a layer of apples on the bottom. Spoon rice on top and add another layer of apples. Add a last layer of rice, dot with butter and bake for 1 hour.