Tapioca Pudding

In the top pan of a double boiler stir the tapioca into the hot milk and cook it over simmering water 3 minutes, stirring frequently. In a heatproof mixing bowl stir 1/4 cup of the sugar into the egg yolks and very slowly blend in the hot tapioca and milk. Return the mixture to the pan over the hot water and continue cooking until it has thickened. Remove the pan from over the water and stir in the vanilla. Cool the mixture slightly and fold in the egg whites, beaten until stiff with the salt and remaining sugar. Pour the pudding into 6 serving dishes and cool and chill it.