Marble Chiffon Cake

Heat oven to 325°F (160°C). In small bowl, combine 2 tablespoons sugar, 2 tablespoons oil, cocoa and 1/4 cup water; stir until smooth. Set aside. Stir together flour, remaining 1 1/2 cups sugar, baking powder and salt in medium bowl; add remaining 1/2 cup oil, egg yolks, remaining 3/4 cup water and vanilla. Beat on low speed of mixer until combined; continue beating on high speed 5 minutes. Beat egg whites with cream of tartar in large bowl, with clean set of beaters, until stiff peaks form. Pour batter in thin stream over beaten whites, gently folding with rubber spatula just until blended. Remove one-third of batter to separate bowl; gently fold in reserved cocoa mixture. Pour half of light batter into ungreased 10-inch tube pan; top with half of chocolate batter. Repeat layers. With narrow spatula or knife, swirl gently through batters to marble. Bake 65 to 70 minutes or until top springs back when touched lightly. Invert pan on heat-proof funnel; cool cake completely. Loosen cake from pan; invert onto serving plate. Spread Vanilla Glaze or Quick Cocoa Glaze over top of cake, allowing glaze to drizzle down sides. In small saucepan over low heat, melt butter. Stir in cocoa and water. Cook, stirring constantly, until mixture thickens. Do not boil. Remove from heat. Stir in vanilla. Gradually add powdered sugar, beating with whisk until smooth. Add additional water, 1/2 teaspoon at a time, until desired consistency.