Can I use BC made only with butter under MMF? Or is it better to use a butter/ shortening blend (which is what I usually do?) Thx!

I've used all butter, it was fine. If it's very hot, shortening and butter mix holds up better because shortening is not soft at room temp the same way butter is. But they have both worked for me. If it is very hot and using all butter, putting on a thinner layer will mean less under there to slide down and bulge. HTH.

Duplicate post, please also see:

http://cakecentral.com/cake-decorating-ftopict-671469-.html

HTH