1 Bring the sugar to the boil with 150 ml water, boil for around 1 minute, then take off the heat and leave to cool.
2 Blend the melon flesh and the ginger to a purée and press through a fine sieve. Mix together the sugar syrup, the melon and ginger purée, the lime juice and the lemon liqueur and pour into a metal container. Place in the freezer and freeze for at least 4 hours, stirring thoroughly with a fork every 20 minutes for the first 3 hours.
3 Once the granita has formed into fine ice crystals, stir once more and spoon into glasses. Pour over the vodka and serve with a spoon.