Mahogany Chiffon Cake
["3/4 c. boiling water", "1/2 c. cocoa", "1 3/4 c. sifted cake flour", "1 3/4 c. sugar", "1 1/2 tsp. soda", "1 tsp. salt", "1/2 c. salad oil", "7 unbeaten egg yolks", "2 tsp. vanilla", "1 c. egg whites (7 or 8)", "1/2 tsp. cream of tartar"]
["Combine boiling water and cocoa; cool.", "Sift together dry ingredients.", "Make a well in flour mixture; add oil, egg yolks, cocoa mixture and vanilla.", "Beat until smooth.", "In a large bowl, beat egg whites and cream of tartar until very stiff.", "Pour egg yolk mixture gradually over beaten whites, gently folding with rubber scraper until blended.", "Pour into ungreased 10-inch tube pan.", "Bake at 325\u00b0 for 70 minutes.", "Invert on funnel; hang until cool."]
["boiling water", "cocoa", "cake flour", "sugar", "soda", "salt", "salad oil", "egg yolks", "vanilla", "egg whites", "cream of tartar"]