Hello, I have noticed that my fondant cakes are cracking after I stack them. Even if they sit for 15 minutes and then stack them it still dries enough where they develop these little tiny cracks ( almost like little cake stretch marks--sorry). I use cornstarch to roll my fondant and wooden dowels also. I am not sure how to fix this problem. Also do most decorators cut their cake layers into very thin layers with this layers of filling or thick layers of cake, maybe that may be my problem as well. Thanks so much.
For fondant cake, your support needs to be a wee bit taller than for buttercream. Just ever so slightly above the top of the fondant.
I agree with Leah. Sounds like the upper tiers are pushing on the fondant of the tier below, causing cracks. Do you ever see cracks on the top tier? If not, then I think we've zeroed in on the problem.
Edited to add: Cracks may appear on the top tier if you're supporting a heavy topper with dowels cut too short.