Grapefruit Sherbet

• 12 oz caster sugar
• 2 large grapefruit
• ¾ pint

Stir the sugar and the finely grated rind of one of the grapefruit into the water in a thick saucepan. Heat gradually, stirring; when the sugar has dissolved, bring the mixture to the boil and boil fast for five minutes. Allow to cool, stir in the juice of the two grapefruits and a squeeze of lemon juice, and put in the freezer tray in the refrigerator; freeze to a mush.

Beat the egg wh