Preheat your oven to 350°F (175°C).
In a medium bowl, sift together the cake flour and ¾ cup of the sugar. Set aside.
In a large mixing bowl, beat the egg whites, cream of tartar, and salt on medium speed until soft peaks form.
Gradually add the remaining ¾ cup of sugar, about 2 tablespoons at a time, beating on high until stiff peaks form.
Gently fold in the vanilla extract.
Sift a small amount of the flour mixture over the egg white mixture and fold in gently. Repeat until all the flour mixture is incorporated.
Pour the batter into an ungreased 10-inch tube pan. Gently cut through the batter with a knife to remove air pockets.
Bake for 40-45 minutes or until the top is lightly browned and the cake springs back when touched lightly.
Invert the pan onto a bottle or funnel and let it hang until completely cool. Run a knife around the edges to release the cake from the pan.