MACAROON FILLING: Beat 1 egg white with vanilla until soft mounds form. Add 1/2 cup sugar, gradually beating until peaks form. Stir in coconut and 1 tablespoon flour. Set aside. Dissolve cocoa in hot coffee. Beat 3 egg whites until soft mounds form. Add 1/2 cup sugar gradually, beating until meringue stands in stiff peaks. Set aside. Add soda to sour cream. Set aside.
Beat 1 1/4 cups sugar, shortening, egg yolks, 1/2 teaspoon salt, 1 teaspoon vanilla, and half of cocoa mixture until light and creamy about 4 minutes. Add 2 cups flour, sour cream and remaining cocoa mixture. Blend well. Fold in egg whites. Turn 1/2 of chocolate batter into a 10 inch tube pan greased on bottom. Place coconut mixture on top of chocolate batter. Cover with remaining chocolate batter. Bake at 350 degrees for 55 to 65 minutes. Cool completely before removing from pan. Frost with chocolate frosting.
