I was watching Buddy (cake boss) and he only puts a crumb coat under the buttercream before putting fondant. Do alot of people do this? Does it help with buttercream not sloshing around underneath? It would save me alot of time to only do one coat but i would be scared you may see it through the fondant.

I meant crumb coat of buttercream under the fondant

I always put in two coats of buttercream, like you said I'm worried about it showing underneath the fondant if it's a light colored fondant and I think it's better for my customers as most of them don't prefer fondant even if it's MMF! 
:)

AI quit using buttercream under fondant, but when I did I used a full layer of buttercream. Now, I use white chocolate ganache. It holds up to the weight of fondant and doesn't slosh around.

 I crumb coat and then put a nice, thick layer of buttercream under my fondant.

ANever crumbcoated a cake, just a thick coating of SMBC, chill, and then fondant.

I'd be pissed if I ordered a cake and all it had was a thin little layer of buttercream under the fondant. Extremely. I want just as much as there would be had it not been covered in fondant.

AI use ganache, but I think that unless you're cutting you cake into giant wedges, you're not really getting the edge of the cake anyway. In fact, when I'm cutting my own cakes, I cut all the icing off the side of the cake to make it easier to get nicer slices. So most people are only getting the icing on the top of the cake anyway.

If I was using buttercream and worrying about it smoothing around, I'd do a crumbcoat amount on the outside and a thicker layer on top.

AI use only a crumb coat underneath fondant. I roll my fondant to about 3mm thickness and never had any issues, even with colored BC under white fondant...

AAZCouture: But there is enough buttercream between the layers. I think she's only asking about the surface of the cake...

A

Both of these. And I can PERSONALLY vouch for the fact people DO NOT LIKE a less than normal coat of buttercream under fondant. Found that out the hard way years ago. Cover a well chilled cake and there will be no sloshing. An all butter butttercreAm helps greatly

A

No kidding! "Mmmm, go ahead and just put a thin layer on, we really just want all the fondant anyways!" Said no one. Ever.

AYea I always put 2 layers cause a lot of people don't like fondant but thanks y'all cleared that up for me lol