Pandan Chiffon Cake without the oil

I chanced upon Table for Two website and she has a recipe for oil-less Pandan Chiffon Cake.  I have another recipe for Pandan Chiffon from Creative Culinaire. It yields nice and soft chiffon but I hesitate to bake it frequently due to the amount of oil added to it.  What greater chance for me to try for an oil-less recipe.  The original recipe from Table for Two calls for cream of tartar but since I do not have it, I made do without. Result of the cake - Nice and tall.  I used a lazy method to whip up the cake hence was rather surprised it turns out well.  I believe the importance is how you whip the egg white and ensure light folding so you do not deflate the air.

Here is the recipe (with slight variation and ommission of Cream of Tartar in the egg white):

5 egg whites
100 gm sugar

5 egg yolks
60 gm sugar (original calls for 100 gm)
150 gm cake flour
180 gm coconut milk + pinch of salt
Pandan paste (original calls for concentrated pandan juice)

Method:

1. Stir Pandan paste into coconut milk.
2. Whip egg yolks and sugar till ribbon stage.   Pour cocnut mixture into it.
3. Separately whip egg whites and sugar till peak stage.
4. Mix (3) and (2) with light strokes. Add in flour gradually. 
5. Pour into 25 cm chiffon pan and bake for 25 mins at 180 degree celcius.