I need help! I have been doing this for a year and I still cannot get the fondant at the bottom of my cakes to lay flat. It seems like there are always a few creases. Luckily I can usually hide them with a ribbon border or piping a border. It drives me crazy so if you have ANY tips I would really appreaciate them!
SERIOUSLY! I am having the same problem! Help!
One tip is to roll your fondant bigger than you need to cover the cake. Normally you would need 8" for the top, 4+4= 8 inch for the side, total 16 inches. But you need more. Roll out a 20 to 22 inch round/square piece to cover an 8 inch cake.
You need more fondant to tent the cake and the creases will be at the ends not up next to the cake bottom. If your not rolling out enough, you are struggling with a small amount of fondant. Picture a can of tuna under a blanket, no creases.
I mix crisco with fondant to make it nice and workable/smooth.
Chill you buttercream iced cake for at least 10 minutes before you put the fondant on it. Barely mist the sides of the cake with clean water to help the fondant stick. Then I roll out the fondant on a roulpat or a piece of plastic sheet (from Walmart). I don't use cornstarch or powdered sugar. But if that works for you, use it.
I hope this helps. I only make fondant cakes for my wedding cake shop.
I also find it helpful to, once you have the fondant almost complete smooth, and most of the excess trimmed, elevate the cake on top of something a bit smaller (quart container, coffee can, etc--or even your turntable, if it's a larger tier) and then smooth the fondant DOWN (this is after you have already gotten all of the folds and creases out, of course). then take a VERY sharp paring knife and trim the rest away. It's important though, that when you elevate the cake you do NOT have a lot of excess fondant hanging down, or the weight will cause the fondant to tear. This is really just to fine-tune the smoothness on the bottom edge and get a nice, clean, final trim.
Also, when smoothing the fondant on the sides, remember, smooth down, not around. start at the top edge and work you way down, pulling the fondant back out away from the cake (not the whole side, obviously, just as much as is creased or folded) as you encounter folds or creases and then smoothing the fondant back onto the cake.