Grandma Leu's Famous Angel Food Cake

If there is one signature recipe our Grandma Leu is famous for, it's her angel food cake. She beats the egg whites by hand (the secret to this recipe) . . . and she sifts the flour an amazing 15 times (secret #2). Don't shortcut anything in this recipe. Believe me, it will not turn out (I've tried). Also, I pre-sift and pre-measure the flour and sugar so it is ready to go when the egg whites are whipped.
It is a labor of love that we all enjoy. Her recipe will live on in this family long after she leaves us.

2 1/2  cups  egg whites, room temperature (14-18 eggs)
Pinch of salt
1-1/2  tsp  cream of tartar
2  cups  sifted granulated sugar
1  cup  plus  3  Tbs  cake flour
1/4 - 1/2  tsp  almond extract
1-1/2  tsp  vanilla

In recent years she used a very large copper bowl to beat the egg whites in, but she didn't used to do this. So if you are fortunate enough to have a large copper mixing bowl, now is the time to use it. Otherwise, use what you have. Just be sure it is squeaky clean.

Also, Grandma has an angel food cake pan that she will not allow for any other use. She claims it affects the rise of the cake (???) I'm not convinced of that, but that's her story and she's stickin' with it.

So let's get started:
In a very large bowl, combine the salt with the egg whites. Let sit to get to room temperature. (Grandma prefers eggs that have never been refrigerated, but she's not on the farm anymore, so that's hard to find).  Using a wire whisk, whip the whites by hand until frothy. Add cream of tartar and continue to whip until stiff. (To check if they are stiff enough, gently turn the bowl to the side. If they run at all, continue to whip some more, but if you over-whip them they will be tough and dry.) Gently fold in the vanilla, almond, and 1 cup of sifted sugar.

Combine the remaining 1 cup pre-sifted sugar, along with all the cake flour. Sift this combination together 5 times if you have a triple sifter. Otherwise you must sift this 15 times before continuing.

Very gently, fold this flour mixture into the egg whites, small amounts at a time. You must do this with extreme care, so the egg whites won't deflate.

Put into an ungreased angel food cake pan. Very gently, cut through the batter with a knife to release any trapped air bubbles. Do this with a gentle hand . . . you don't want to mess it up now!

Bake @325 degrees for one hour. Remove from oven and turn the cake (still in the pan) upside-down over a large metal kitchen funnel, or a soda pop bottle. Cool it this way until the cake is completely cooled.
Cake needs to have good air circulation around the bottom while cooling.

Run a long sharp knife all around the outside and inside of the cake to release it from the pan. Grandma uses a plain powdered sugar frosting for this cake, but I much prefer the angel food cake frosting found under Frosting in this recipe collection.