Preheat your oven to 175°C (350°F). In a separate bowl, sift the cake flour and confectioners sugar together 5 times, then set it aside.
Using a large and spotless mixing bowl, begin whipping the egg whites with a pinch of salt until it becomes frothy. Add cream of tartar and continue beating until you see soft peaks appearing. While still beating, gradually add sugar until you reach the point where the peaks are very stiff. Finally, stir in vanilla extract.
With quick movements, gently fold in the flour mixture. Then pour the mixture into a 10-inch tube pan.
Bake for 45 minutes at 175°C (350°F).
