method
1. Heat the sugar in the water over a medium heat, stirring constantly until the sugar has dissolved. Boil for 5 minutes.
2. Add the finely grated peel and the lemon and both oranges to the syrup. Leave until completely cold.
3. Stir the juice of the lemon and oranges into the syrup. Add the orange flower water if you are using it.
4. Pour the granita mixture into a very shallow freezer-proof dish and freeze until nearly firm.
5. Stir the ice crystals at the edge of the dish into the centre several times but take care not to break them up — the granita should be fairly coarse.