This ice cream has an almost magical consistency and is very soft and light, even if you bring it straight out of the coldest deepfreeze. At Christmas, try it with the Christmas pudding as an alternative to brandy butter or cream. For a dinner party, top it with crunchy, caramelised almonds.
Whisk the egg whites in a large bowl with the salt until they begin to stand in soft peaks. Dissolve the demerara sugar with the water in a saucepan, stirring over a low heat, then increase the heat and boil fiercely, without stirring, for 3 minutes. Pour immediately on to the egg whites, in a thin stream, whisking all the time with an electric whisk at high speed. Gradually whisk in the vanill