Low Fat Chiffon Cake made with Applesauce [低脂戚風蛋糕]

Lately, I have been trying to come up with a healthy version of chiffon cake. Traditional chiffon cake usually requires about 1/3 cup of oil for an 9 inch chiffon cake. I substitute most of the oil with applesauce, and only need 1 Tbsp of oil for this recipe. Since applesauce contains sugar, I can also use much less sugar. This healthy, fluffy and light chiffon cake is surely one of my family's favorites. Enjoy and have fun cooking, my friends! :)

Ingredients:
1.5 cup Cake flour/Low gluten flour
2 tsp Baking powder
1/2 tsp Kosher salt
8 Large eggs
5 Tbsp Sugar (divide into 4 Tbsp for egg yolks & 1 Tbsp for egg white)
1/3 cup Applesauce
100ml Water
1 Tbsp Grapeseed oil
1 tsp Vanilla extract
1 tsp Cream of tartar

Method:

1. Preheat oven to 350˚F.
2. Separate the egg yolks from egg whites.
3. Sift flour and baking powder together. Add salt (because Kosher salt is a little too big to go through the sifter)
4. Beat together 8 egg yolks and 4 Tbsp sugar with an electric beater. Beat the mixture until it becomes pale yellow and 'ribbons' when lifted. For a ribbon-like picture, you can check my other post, Custard fillings.
5. Add applesauce, water, vanilla extract. Whisk lightly to combine.
6. Add the sifted flour & salt. Stir lightly to combine.
7. Place egg whites and cream of tartar into a clean mixing bowl. Beat on high speed until it becomes foamy. Decrease to low speed and add the remaining 1 Tbsp sugar. Mix well and turn back to high speed again. Beat for about another 2 minutes.
8. Divide beaten egg white into 3 equal portions. Add 1/3 of the egg white to the egg yolk batter. Lightly whisk until well mixed. Then use folding method to fold in the second 1/3 of egg whites into the batter.  Then, fold in the last 1/3 of the egg whites.
9. Lightly grease the 9 inch tubed pan. Transfer the batter into the pan.
10. Bake at 350˚F for 20min. Then, decrease the oven temperature to 325˚F and bake for another 25 to 30 min. The total baking time should be around 45 to 50 min. You can insert a wooden stick into the cake after 45 min, and if the stick is 'clean' (no sticky batter) after pulled out, that means it's done.
11. Take the cake out of the oven and turn it upside while still attached to pan for cooling.
12. Take the cake out of the pan after it's completely cooled.

Note:

1. I can make this cake without adding that 1 Tbsp of oil. However, I am not a supporter of fat free diet. We need fat, but have to eat the good fat, such as grapeseed oil or olive oil..etc...
2. Don't use olive oil in this recipe though. It makes the cake taste funny.
3. Take the eggs out of the refrigerator a little bit early to let it 'warm' back to room temperature. It will yield better result.
4. The rule of thumb for adding cream of tartar is 1/8 tsp of it per each egg white. so, in this case, we have 8 egg whites, and we need a total of 1 tsp of cream of tartar.
5. Cream of tartar is a byproduct of winemaking. It is an acidic salt. In cooking, it changes the pH value of egg white to a slightly acidic range, which helps stabilizing egg whites, increasing their heat tolerance and volume. Some people said it could be substituted with lemon juice. I haven't tried and am not sure how much to use yet, but I believe it should work.
6. I don't use table salt. I love kosher salt or sea salt for cooking. In my opinion, they are not just healthier, but also taste better too.
7. Since this recipe doesn't use too much oil, you still need to grease your pan even if it's a non-stick one cause the cake sticks.
8. Folding method is needed in making fluffy cakes, especially we don't use much oil here. It helps minimize the gluten formed (the chewiness in bread) while mixing.
9. I like to set a slightly higher temperature at the beginning because it helps expanding the cake better. after the cake is expanded, I decrease the temperature such that it will continue to cook without browning the surface too much.