Put the gooseberries in a saucepan with the sugar and 50 ml (2 fl oz) water. Cook gently, covered, until the fruit is soft. Puree in a blender or food processor, then push through a nylon sieve and leave until cool.

Sprinkle the gelatine in 45 ml (3 tbsp) cold water in a small bowl and leave to soak for 2 - 3 minutes. Place the bowl over a saucepan of simmering water and stir until dissolved. Leave until lukewarm, then stir into the gooseberry puree with the yogurt.

Whisk the egg whites until stiff but not dry. Fold into the puree.

Pour into a rigid freezer container and freeze for about 2 1/2 hours or until almost frozen. Remove from the freezer and beat or whisk well, or blend in a food processor. Return to the freezer and freeze for at least

4 hours, until firm.

Before serving, transfer to the refrigerator for about 30 minutes to soften slightly.