Never made Orange Chiffon Cake myself, but it does sound good. Found these recipes for you -- hope they help.
Orange Chiffon Cake - Regal Orange Chiffon Cake
Serves/Makes:12
Ingredients
2 cups (475 ml) all-purpose flour
1-1/2 cups (350 ml) granulated sugar
1 tbsp (15 ml) baking powder
1/2 tsp (2 ml) salt
3/4 cup (175 ml) cold water
1/3 cup (80 ml) cooking oil
3 large egg yolks
1 tbsp (15 ml) grated orange peel
1 tsp (5 ml) vanilla
8 large egg whites
1/2 tsp (2 ml) cream of tartar
powdered sugar
Preparation
In large bowl, stir together flour, granulated sugar, baking powder and salt. In another large bowl, combine water, cooking oil, egg yolks, orange peel and vanilla.
Make well in center of flour mixture; add egg yolk mixture. Beat with electric mixer on low speed until combined. Wash beaters thoroughly. In a large bowl, beat egg whites on high speed until frothy. Beat in cream of tartar and continue beating just until stiff peaks form (tips stand straight). Pour egg-yolk batter in a thin steam over entire surface of beaten egg whites; fold in lightly by hand. Pour batter into an ungreased 10-inch tube pan. Bake in a 325 degree (175 C.) oven for 55 to 60 minutes or until top of cake springs back when touched lightly. Remove from oven; invert in its pan.
Cool in pan. Gently loosen side of cake from pan with a spatula or knife. Invert onto a serving plate and remove pan. Sift powdered sugar over cake.
Got that one here:
http://online-cookbook.com/goto/cook/rpage/000E1E
Here's another one that sounded good:
Orange Chiffon Cake
2 1/4 cups cake flour (not self-rising)
1 1/2 cups sugar
1 tablespoon double-acting baking powder
1/2 teaspoon salt
1/2 cup vegetable oil
7 large egg yolks
3/4 cup fresh orange juice
2 tablespoons freshly grated orange zest
2 tablespoons vanilla
9 large egg whites
1 teaspoon cream of tartar
Into a large bowl sift together the flour, 3/4 cup of the sugar, the baking powder, and the salt. In a bowl whisk together the oil, the egg yolks, the orange juice, the zest, and the vanilla and whisk the mixture into the flour mixture, whisking until the batter is smooth.
In the large bowl of an electric mixer beat the egg white with a pinch of salt until they are foamy, add the cream of tartar, and beat the whites until they hold soft peaks. Add the remaining 3/4 cup sugar, a little at a time, and beat the whites until they hold stiff glossy peaks. Stir one third of the whites into the batter to lighten it and fold in the remaining whites gently but thoroughly.
Spoon the batter into an ungreased 10-inch tube pan, 4 inches deep, with feet and a removable bottom, and bake the cake in the middle of a preheated 325oF oven for 1 hour, or until a tester comes out clean. Invert the pan immediately onto a rack and let the cake cool completely in the pan upside down on the rack. Run a long thin knife around the outer and tube edges of the pan and turn the cake out of the pan onto the rack. Using a serrated knife cut the cake in half horizontally.
Frosting:
2 cups well-chilled heavy cream
3 tablespoons Grand Marnier or other orange-flavored liqueur
2 teaspoons freshly grated orange zest
1/4 cup sugar
In a large bowl, chilled, with an electric mixer beat together the cream, the Grand Marnier, the zest, the sugar, and a pinch of salt until the mixture holds stiff peaks. Transfer the bottom layer of the cake to a platter, spread some of the frosting on it, and top it with the remaining layer. Spread the remaining frosting on the top layer and side of the cake.
Got that one here:
http://dinnercoop.cs.cmu.edu/dinnercoop/Recipes/jody/OrangeChiffonCake2.html
