Soak tapioca in water for 30 minutes in a 1 1/2 quart saucepan. Do not drain remaining water, if any.
Add milk, salt, 1/4 cup sugar and lightly beaten egg yolks to tapioca and stir over medium heat until boiling. Simmer uncovered over very low heat for 10-15 minutes. Stir often.
Beat egg whites with remaining 1/4 cup sugar until soft peaks form. Fold about 3/4 cup of hot tapioca into the egg whites, then gently fold mixture back into saucepan. Stir over low heat for about 3 minutes. Cool 15 minutes then add vanilla.
Serve warm or chilled, plain or with fruits, nutmeg or coconut mixed in.
4 servings