I just used a recipe that I found on here that I used for my daughters bday cake over the weekend. It turned out wonderful. Went on the cake easy. I posted a pic of the cake I did in my photos. It is the Justin Bieber cake.
The recipe I found in the recipes here on cake central but don't remember who it was by:
6oz white choc. (I used guiradelli(?) white choc. chips
1/4 heavy cream
(mix these 2 together and microwave until melted) recipe said about a 1.5 min. but I needed more melting time at 10 sec. intervals)
While the choc. mixture was cooling:
1 cup butter
2lbs powder sugar.
I had to use almost 1/2 c extra cream to thin the buttercream mixture before adding the white choc. mix.
I had so many compliments at the party on how good it tasted. It was very easy to spread on the cake too. I have been using a buttercream recipe also found here on CC and I was having a very hard time getting it to cover the edges without it rolling off. With the white choc. buttercream recipe I had absolutely no problems whatsoever.
For the exact recipe you can do a search on recipes here on CC and I think it is the 2nd recipe.