The chiffon cake has the richness of the butter cake, and the fluffiness of the sponge. It is prepared with oil(corn or sunflower), eggs, sugar, flour, baking powder, and flavorings. Chiffon is traditionally baked in a tube pan, but any spring-form pans work good too.
- In a small pot stir together half tablespoon of cornstarch and 3 tablespoons of water until smooth. Heat the mixture over the low fire while stirring until the starch thickens. Set aside to cool. Prepare a deep baking tray half-filled with warm water and place a wire rack atop. Set it on the second lower shelf in the oven. Start preheating to 175C/350F.
- Sift the powdered sugar into a bowl. Whisk together AP flour, cornstarch, salt, and baking powder in a bowl. Combine chocolate and grape juice into a sauce pan. Melt chocolate over low heat, stirring occasionally. Place melted chocolate mixture, vanilla extract, egg yolks and vegetable oil in a larger bowl. Whip until completely blended. Gradually sift flour mixture into chocolate mixture. Mix until thoroughly combined.
- Beat the whites slowly with a pinch of salt until they are frothy, then add in lemon juice to the foam. Salt and acid will help stabilize the foam. Continue beating the whites and gradually add in sifted powdered sugar when they have almost reached the soft peak. After powdered sugar has been beaten into the meringue and it forms soft peaks, add in cornstarch mixture, beating to firm peaks. Cornstarch helps to keep the meringue firm. With a rubber spatula fold 1/3 of meringue into the yolk batter to lighten it (unnecessary too thoroughly blended) . Quickly but gently fold the remaining meringue into chocolate batter in two additions, folding after each addition just until no white streaks remain. Pour the batter into an ungreased 10 or 11-inch round pan and place it on the top of prepared tray. (This resembles to a bain marie, ensuring that chiffon cake bakes gently and evenly, without risking water trapping through springform to the cake during the baking) . Bake for 65-75 minutes, until wood pick inserted in the cake comes out clean. Turn on a wire rack to cool. You can enjoy the cake as it is, or with desired sauces or toppings, or slice it horizontally into 3-6 layers to make a cream layer cake.