Place the rack in the lower part of the oven. Preheat the oven to 325°F (170°C).
In a large bowl, beat the egg whites until soft peaks form.
Add the cream of tartar and beat again until stiff peaks form, then gradually add the sugar.
Sift the flour and add a pinch of salt.
Fold the flour into the egg white mixture. Add the vanilla.
Pour into an ungreased tube pan and bake for about 45 minutes, or until the cake springs back when pressed lightly with a finger.
