Preheat your oven to 325°F and adjust the rack to the lower-middle position.
Use a food processor to make your sugar finer by pulsing it. Set aside 1 cup of the processed sugar.
Add flour, corn starch, and salt to the remaining sugar in the food processor, and mix them well.
In a large mixing bowl with a whisk attachment, beat egg whites and cream of tartar until bubbly.
Increase mixer speed, add the reserved cup of sugar gradually, and beat until soft peaks form.
Sift the flour mixture into the egg whites in three parts, folding gently each time with a rubber spatula.
Transfer the mixture into an ungreased tube cake pan and bake for 42-47 minutes, until golden.
After baking, invert the cake pan onto a paper cup or similar item, and let it cool upside down for 3 hours. Then, carefully remove the cake from the pan and transfer it to a serving dish.