Move the top oven rack to the lowest position. Preheat oven to 350°F. A tube pan with removable bottom works best for this recipe. Do not grease or spray the pan.
In a medium bowl, sift together the flour, cornstarch, and ¾ cup of the sugar. Set aside the extra sugar and the sifted ingredients.
⅞ cup all-purpose flour, 2 tablespoons cornstarch, 1½ cups granulated sugar
In a large bowl, using a hand or stand mixer, beat the egg whites, cream of tartar, vanilla, and salt on a high speed until soft peaks have been reached.
12 egg whites, 1½ teaspoons pure vanilla extract, 1½ teaspoons cream of tartar, ½ teaspoon kosher salt
At this point, slowly add the remaining sugar to the egg mixture while continuously beating into stiff peaks.
1½ cups granulated sugar
Once the egg whites have reached a stiff peak, use a spoon or spatula to gently fold the dry ingredients into the eggs just until blended.
Pour the batter into the ungreased tube pan. Bake for 40-45 minutes, just until the top is browned, completely dry, and has started to crack.
Once done baking, immediately take the pan out of the oven and turn it upside on top of a bottle to prevent the cake from collapsing. Cool upside down for 1 hour before removing from pan. Once cooled, to remove the cake, slide a knife along the edges of the pan until it has been released.