Baked Prune Pudding

In a medium saucepan, simmer the prunes in water until soft. Drain and purée.

Combine the purée in a saucepan with the sugar and heat until the sugar dissolves. Add the lemon juice and vanilla.

Preheat oven to 150 C / Gas mark 2.

Beat the egg whites until frothy, add the cream of tartar, and beat until stiff. Fold the prune purée into the egg whites.

Pour into a buttered and sugared 2 litre baking dish and bake in preheated oven until nicely browned. Refrigerate and serve chilled with whipping cream.