I'm making a mint & chocolate 9x13 cake for a shower.  I have a mint crunch filling I want to use with light mint frosting.  I'm starting to chicken out of torting the cake and don't want to double up with another layer.  So my question:  Has anyone had experience with covering a cake with a first layer of crunchy chocolate-y filling and then topping it with butter cream frosting?

Personally, I would just go ahead and torte the cake. I have never put frosting on top of filling and it seems like a recipe for a hot mess. Especially if the icing will be white. If you really want to do it that way, experiment with it on a cake board or cupcake. 

A

I torte any cake i do. What ever shape or size.  I don,t make 2 layers0f 9x13 ,  unless the client is willing to pay for 2 layers.

When I want to torte a cake I always freeze it then defrost - when it is not quite fully defrosted that is when I will cut it. As a home baker I haven't had much practice so I find that having the cake semi solid makes it so much easier. I also measure and mark my cuts with a ruler (that I use just in the kitchen) and a knife so that I have a line to follow, otherwise I run off course.

AIf you haven't already baked the cake, you can just bake it in 2 thinner layers and stack them instead of cutting in half with a knife.

I third the "hot mess" statement.