Melon Sorbet

3 Ripe sweet melons, halved and de-seeded
4 Oz. Icing sugar, sifted
6 Tbsp. White wine vinegar
2 Large Egg whites

Scoop flesh from melons and place in a food processor with sugar and vinegar. Blend to a purée. Place in a freezer-proof container, cover and freeze for 4-5 hours. Whisk egg whites until stiff, then blend with mushy sorbet. Freeze until solid. Let stand at room temperature for 10-15 minutes before serving.