Wash the gooseberries; there is no need to top and tail them. Place in a saucepan with the water. Bring up to the boil, cover and simmer very gently for 10 minutes until tender and quite soft. Draw off the heat, add the sugar and stir to dissolve it in the heat of the pan. Then rub the fruit and juices through a sieve to make a purée. Discard the skin and pips that remain in the sieve and allow the purée to cool.
Add the unbeaten egg white to the cream and whisk both together until thick and light. Fold in the gooseberry purée. Spoon into a serving dish or individual glasses and chill for several hours until firm before serving. This looks pretty sprinkled with a few chopped pistachio nuts for decoration.