Actually, it does give structural support. The reason I know this is, I once tried to trim some of the dark brown section off a wonder mold cake. (They take forever to bake) When I inserted the Barbie, it formed cracks on both sides and I had to re-bake it. That's the only time my cake has ever cracked open, so in this case the outer layer does provide support.
6/1/13 at 1:23pm