I have only made 3 fondant covered cakes and will be making one this month. I was told before I did the other ones that your cake has to be heavy so I used yellow cake box mix and I believe I added a few extra eggs. Is this true or are there any mixes that aren't good when covering the cake in fondant? Also, is there any fillings that shouldn't be used? I have only ever used BC as the filling? Any advice would be greatly appreciated : )
I've made plenty of boxed mix cakes for use with rolled fondant. No, your cake does not have to be heavy, just sturdy enough to take the weight of the icing with fondant. I've never heard that a cake with rolled fondant icing has to be heavy.
You can use any type of filling, as long as you can support the upper layers.
Yes I was told that the cake has to be denser in order to hold all the weight but what that really means is don't make an Angel food cake or anything light and fluffy and put fondant over it. Any filling will do just make sure you create a dam with BC just like any other time.
I've only made 2-3 fondant cakes, but I used a box mix with dream whip and an extra egg ... held up fine. I rolled the fondant really thin (used choco-pan, which is designed to be rolled thin).
I put fondant on a cake mix all the time, using no extra ingredients in the mix. I use a choc. fondant and roll it THIN. I also put an normal layer of icing on the cake.