In a large bowl, sift the cake flour, 1/2 cup sugar, and salt 3 times.

In the bowl of an electric mixer, beat the egg whites on high for 1 minute. Add the cream of tartar and beat just until soft peaks start to form. Add the orange extract and slowly add the rest of the sugar; continue beating until stiff peaks form.

fold half the flour mixture into the egg whites with a wire whisk until incorporated, then fold in the second half. Spoon the batter into an angel food cake pan and bake in the center of the oven for 45 minutes or until a knife inserted in the center comes out clean.

To help the cake retain its shape, invert the cake pan over a wine bottle and allow the cake to cool upside down for at least an hour.