So I tried subbing coconut palm sugar in place of castor sugar in a sponge/castella recipe (the whipping of eggs + sugar part) knowing it might not work because palm sugar is more moist. Regardless, I wanted to try anyways and the cake came out chewy and dry.
What's a good "raw" sugar to use in a sponge cake? I know there's a lot of controversy with turbinado and demerara not being "raw" but I find that they would be a good alternative if I just grind it up.
Also, is it possible to half the sugar in these types of cakes when it's required to increase the volume/thicken the batter?