I do have a heating core, but I've found that allergen friendly cakes don't always bake well in larger sizes. This is especially true of egg free cakes since they lack key structure. If you can get it baked through, the chance of cracking or crumbling while handling it is pretty high. I've found that Wacky Cake doesn't do well in anything bigger than 9x13 - it takes so long for the center to heat up that the single acting leavening just fizzles out. Gluten/wheat free cakes are very difficult...