I have a favorite SMBC that I'd like to make chocolate.  I've read in various places that some add straight cocoa powder, some mix cocoa powder with water, some use melted chocolate.  What is your preferred method?  What chocolate do you use?  High end chocolate, low end?  Semi sweet?  60% cocoa?

Thank you for your help!
Christina

I just add melted chocolate, usually in the range of 60-70%. I would only use a high end chocolate myself. I generally use Callebaut or Valrhona, but use whichever chocolate you like best. I just add it until it tastes like I want it too. 

I use cooled melted chocolate. I'm a huge lover of premium chocolate but I feel its a waste in this case, just buy a decent semi-sweet (60% at least)

I also add cooled melted chocolate. I've done a milk chocolate variation if I don't want an overpowering chocolate flavour but want a touch more sweetness. Dark chocolate you definitely get a good punch of flavour. For each 1LB butter used in the buttercream I use 250g-300g chocolate.