Measure egg whites, adding or removing whites as needed to equal 1 1/2 cups. Place in a mixing bowl and let stand at room temperature for 30 minutes.
Preheat oven to 350F.
Meanwhile, sift confectioners' sugar and flour together three times; set aside.
Add the cream of tartar, both extracts, and the salt to the egg whites and beat on high speed using an electric mixer. Gradually add the granulated sugar, beating until sugar is dissolved and stiff peaks form.
Fold the flour mixture into the egg white mixture, 1/4 cup at a time. Gently spoon into an ungreased 10 inch tube pan. Cut through the batter with a knife to remove air pockets.
Bake at 350 degrees F for 40-45 minutes or until the cake springs back when lightly touched. Immediately invert the pan. Cool completely before removing the cake from the pan.
Make sure you let the egg whites sit for 30 minutes at room temperature before you whip them. Egg whites are imperative to the success of this recipe. They work as the leavening agent that gives the cake its rise.
Cream of tartar will help stabilize the egg whites leaving you with a fluffy, light cake.