Preheat Oven:
Preheat oven to 350°F (175°C). Have an ungreased 10-inch tube pan ready.
Prepare Dry Ingredients:
Sift together cake flour and 3/4 cup of the sugar. Set aside.
Whip Egg Whites:
In a large mixing bowl, beat egg whites with an electric mixer on medium speed until foamy. Add cream of tartar and salt. Continue beating until soft peaks form.
Add Sugar Gradually:
Gradually add remaining 3/4 cup sugar, about 2 tablespoons at a time, while continuing to beat until stiff peaks form.
Add Flavorings:
Gently fold in vanilla extract and almond extract (if using).
Fold in Flour:
Sift 1/3 of the flour mixture over the egg whites and fold gently using a spatula. Repeat two more times until all flour is incorporated. Be careful not to deflate the batter.
Transfer to Pan:
Spoon batter into the ungreased tube pan. Smooth the top with a spatula.
Bake:
Bake for 35–40 minutes, or until cake springs back when lightly touched and a toothpick inserted into the center comes out clean.
Cool Cake:
Invert the pan immediately and let the cake cool completely, about 1–2 hours, to maintain height and texture.
Remove from Pan:
Run a knife around the edges and center tube to release cake. Carefully lift out and slice.