I think this is it. After searching long and hard for the best chiffon recipe, I found the best from "America's Test Kitchen". I took the basic recipe and have been having fun experimenting with different versions. I have made a chocolate one, a green tea one, a black sesame one and a banana flaxseed one.
Call me crazy, but I get an idea in my head that if I put some healthy ingredient in a stereotypically non-healthy treat that I legitimize its inclusion in my diet. Thus, I have included ground flaxseed into my Banana Chiffon cake recipe. People who don't care for it can omit it from the recipe. The amount included is small enough that it is barely detectable. Finely chopped nuts of some sort would be an acceptable replacement.
Note: America's Test Kitchen uses the "dip and sweep" method of measuring cake flour. Do not presift before measuring the flour or you will end up with a very different cake.
1 ½ cups sugar
1 1/3 cups plain cake flour (measure unsifted)
1 ¼ tsp baking powder
¼ tsp baking soda
½ tsp salt
7 large eggs, 2 left whole, 5 separated (at room temperature)
1/3 cup vegetable oil
1 tsp vanilla extract
½ tsp cream of tartar
2/3 cup water
1 cup very finely mashed ripe bananas (about 2 large or 3 medium) [make sure bananas are very ripe—with brown spots on the skin]
½ cup ground golden flaxseed
1. Adjust oven rack to lower-middle position and heat oven to 325°F. Whisk sugar, flour, flaxseed, baking powder and salt together in large bowl (at least 4-quart size). Whisk in two whole eggs, five egg yolks (reserve whites), water, oil and extract until batter is smooth. Stir in bananas.
2. Pour reserved egg whites into large bowl; beat at low speed with electric mixer until foamy, about 1 minute. Add cream of tartar, gradually increase speed to medium-high, then beat whites until very thick and stiff, just short of dry, 9 to 10 minutes with handheld mixer or 5 to 7 minutes in standing mixer. With large whisk, fold whites into batter, smearing any blobs of white that resist blending.
3. Pour batter into ungreased large tube pan ( 9 inch diameter, 16-cup capacity).
4. Bake cake on lower middle rack in oven until wire cake tester inserted in center comes out clean, 60-70 minutes. Immediately turn cake upside down to cool. If pan does not have prongs around rim for elevating cake, invert pan over bottle or funnel, inserted through tube. Let cake hang until completely cook, about 2 hours.
5. To unmold, turn pan upright. Run frosting spatula or thin knife around pan’s circumference between cake and pan wall, always pressing against the pan. Use cake tester to loosen cake from tube. For one-piece pan, bang it on counter several times, then invert over serving plate. For two-piece pan, grasp tube and lift cake out of pan. If glazing the cake, use a fork or a paring knife to gently scrap all the crust off the cake. Loosen cake from pan bottom with spatula or knife, then invert cake onto plate. (Can be wrapped in plastic and stored at room temperature 2 days or refrigerated 4 days.)