1.Combine apples, 2 tablespoons of the caster sugar and water into a medium saucepan. Cook, covered, over low-medium heat until very soft. Cool.
2.Whip cream in bowl until soft peaks form.
3.Beat yolks with half a cup of caster sugar in a small bowl with an electric mixer until pale and thick. Fold into the whipped cream.
4.Beat the egg whites and remaining caster sugar in a clean, small bowl with an electric mixer until stiff peaks form. Fold into cream mixture, then fold in the cooled apple puree and cinnamon. Pour into a freezer-proof container, cover and freeze overnight.
5.Finely chop mint and sugar together and sprinkle over ice-cream.
Not suitable to microwave.Note