Preheat oven to 350 degrees F (175 degrees C). Grease two 9-inch round pans.
Sift and measure cake flour. Add salt and baking powder, and sift again.
In a large bowl, beat shortening until smooth. Add sugar gradually, and beat until fluffy. Add sifted ingredients alternately with milk and flavorings (see Cook's Note). Beat thoroughly after each addition.
Beat egg whites until stiff, and fold into mixture. Pour batter into prepared pans.
Bake in preheated oven until cake springs back when lightly touched with a fingertip and a toothpick inserted in the center comes out clean, 25 to 30 minutes. Allow to cool completely before frosting.
