Chiffon Cake

Directions

1. 1
   ["*Separate the eggs carefully; even a small amount of yolk in the whites will prevent them from beating up properly.", "In a large mixing bowl, beat the egg whites with the cream of tartar or lemon juice until foamy. Gradually add 1/2 cup of the sugar and continue beating until stiff and glossy. Set aside.", "Whisk together the remaining 1 cup sugar with the flour, baking powder and salt. In a separate bowl, beat the oil, milk, egg yolks and flavorings until pale yellow. Add the dry ingredients and beat until well blended, about 2 minutes at medium speed using a stand mixer, or longer with a hand mixer.", "Gently fold in the whipped egg whites, using a wire whip or cake blender. Be sure to scrape the bottom of the bowl so the batter is well-blended. Pour the batter into an ungreased 10-inch tube pan or angel food pan, or two 9-inch round ungreased cake pans. Bake the cake in a preheated 325F oven. If it's in a tube or angel food pan, bake it for 50 minutes, then turn up the heat to 350F for the final 10 minutes, making a total baking time of 1 hour. If you're using two 9-inch cake pans, bake for about 40 minutes at 325F, then 10 minutes more at 350F. Don't open the oven during the first", "Yield: One cake, about 18 servings", "To assemble the cake (if you've made a tube-shaped cake), cut a 1-inch slice off the top of the cake, and reserve it. Slice a 3-inch-deep ring out of the middle of the cake, leaving 1-inch walls on each side. Pull out pieces of the cake to make a 3-inch \"trench\"" in the cake. Don't cut through to the bottom of the cake. Fill the trench with chocolate filling. Place the top back on the cake and refrigerate it until ready to frost. If you've made round layers