Preheat oven to 375°F (190°C). Wash an angel food tube pan with hot soapy water to ensure it is grease-free. Let it dry completely. Sift flour and ¾ cup confectioners' sugar together three times; set aside.

In a mixing bowl, beat egg whites and salt on high speed until foamy. Add cream of tartar, vanilla, and almond extracts; beat until soft peaks form. Gradually add 1 cup white sugar, continuing to beat until stiff peaks form.

Sift approximately ¼ of the flour mixture over the beaten egg whites and fold gently with a flat spatula. Repeat this process with the remaining flour mixture in four parts. Pour the batter into the prepared tube pan. Use a knife to gently cut through the batter to remove air pockets.

Bake for 30 to 35 minutes until an inserted wooden skewer comes out clean. Invert the pan onto a wire rack and let it cool for 1 hour.