I made a cake with ganache and covered it with fondant..it was pretty smooth and i loved how easy it was to put the fondant on...

but when i cut the cake..the top seemed a bit hard (i think the ganache was hardened a lot)...and then when i sliced the cake and put it on the plate, the ganche part kind of came away from the cake...like it had stuck to the fondant...does this happen with any of you...

what type of chocolate do you use for ganache? dark chocolate? how much cocoa? 70%?

I use whatever I can get or afford, i'm still experimenting with ganche under fondant, but I must say, so far, I like it better. I've only used semi-sweet morsals so far. I bought Lindtz white choc for a wedding cake i'm doing, but havn't done it yet..8/14.
I wanted the best quality i could find. My square cakes in pic's are ganache. Mine cut fine, not sure if stuck to the fondant, it was a pretty thin layer. compared to BC. I use a clean, warm, non-cearated(sp?) knife. I use 2:1 ratio, in weight! a 3:1 for white. My only issue is getting it smooth enough. Maybe i'm picky, or maybe it's the morsals, because I did read you should use at least a certain % of cocoa in your chocolate.
Here is a great thread, sit when you have time...lol, and enjoy.
http://cakecentral.com/cake-decorating-ftopict-633264-.html

How hard was your chocolate at room temperature before you put it in your cake. Mine I can run a butter knife through it but with some resistance. But it doesn't break or crack. I used the bakers semi-sweet for my chocolate ganache under fondant. I am trying my hand at white chocolate under fondant for the next cake, and white chocolate seems to be a bit pickier than regular chocolate.