My friend Gay Bilson serves this as an appetiser at her restaurant, Berowra Waters Inn, in Sydney, Australia. It is one of the best things I have ever eaten. All at once it is refreshing, sour and salty – everything that you could need to sharpen the appetite. The little biscuits that go with it are perfection.

There is enough for 25 people in this recipe, but only enough to serve as a small taster which,