Halve, core and coarsely chop the apples (leaving on the skins which will add flavour and colour to the sauce). Put into a saucepan along with the pared lemon rind and water. Cover with a pan lid and cook gently for about 10 minutes, or until apples are soft. Draw off the heat.
Add the sugar and stir until dissolved. (The heat of the pan will be sufficient.) Press apples through a nylon