Using a small saucepan, soften gelatin in the cold water then stir in the sugar. Cook over low heat stirring constantly for 2-3 minutes or until hot. Do not boil.
In the top of a double boiler beat the egg whites with an electric beater until they form stiff peaks. Put the pan over boiling water then add cream of tartar and beat 2 minutes. Pour the gelatin and sugar mixture slowly into the beaten egg whites while beating at a high speed to stiff peaks. About 1 minute.
Pour out the hot water from the bottom of the double-boiler and fill it with ice water. Add vanilla and then beat another 3 minutes.
