So trying this...

GREEN  APPLE  SORBET

(adpated from Decadence by Philip Johnson)
makes about 1.5 litres (6 cups)

750g (1.6lbs) granny smith apples, unpeeled, cored, and quartered
juice of 1/2 a lemon
250ml (1 cup) water
375g (1.5 heaped cups) caster sugar
3 teaspoons calvados, optional
1/8 teaspoon liquid green food colouring, optional

Place the apples, lemon juice, water, and sugar in a medium saucepan over high heat. Bring to the boil, then reduce to a simmer. Cook the apples until they are extremely soft, about 20 minutes. Remove from the heat and allow to cool to room temperature.

Once the apples have cooled transfer them to a blender and blend until the mixture becomes a smooth puree. Strain the mixture through a fine sieve. Stir through the calvados and green food colouring, if using. Refrigerate the apple mixture until cold.

Remove the mixture from the fridge and churn in an ice cream machine according to the manufacture's instructions.

Once adequately frozen, transfer the sorbet to a container, cover tightly, and place in the freezer for a minimum of 4 hours.