Sift powdered sugar into a measuring bowl until you have 1 ½ cups.
Sift flour and powdered sugar together, three times.
In a large mixing bowl add egg whites, cream of tartar and salt.
Beat until foamy.
Gradually add sugar and beat until stiff peaks form. Gradually increase the speed while doing this.
Gently fold in flour and powdered sugar mixture.
Pour into a tubed pan.
Cut through with a knife very gently.
Bake in a preheated 375 degree oven for 30-35 minutes.