Chocolate Angel Food Cake Recipe

Sift flour and cocoa together three times; set aside. In a large bowl, beat the egg whites until foamy. Sprinkle with cream of tartar and beat until soft peaks form. Gradually add sugar, about 2 tablespoons at a time, beating until stiff peaks form. Blend in vanilla. Sift about a fourth of the flour mixture by fourths. Pour into an ungreased 10-in. tube pan. Bake at 325° for 1 hour. Turn off the oven, but let cake sit in the oven for 5 minutes. Removed from the oven and immediately invert pan; cool. Loosen sides of cake from pan and remove. Yield: 12 servings.