I ran out of granulated sugar for a cake recipe. Will XXX sugar, or another sugar/sweetener be a good sub? I also have brown, turbinado, and splenda.
The only functional replacement of what you've mentioned would be the turbinado, which is typically a slightly coarser, unbleached version of regular granulated.
Confectioners/XXX sugar is fine ground into powder and will not provide the aeration or structure/bulk to perform in a cake. Brown sugar could possibly work, but will alter your flavor profile. Splenda just isn't that functional.
Best of luck.
In the future, it'll help if you give more info on the type of cake/product you're making.
Yeah I wouldn't use confectioners/powdered sugar as it is actually very finely ground sugar and corn starch. You don't want to add more corn starch to your recipe!Totally agree with @StevenXavier - turbinado is really the only true substitute unless the Splenda is specifically a baking version/mix.