Yummy peanut butter filling? TIA!

I used this recently. It was super yummy. Can't remember now if I followed exactly as written or if I adjusted to make it softer.
http://cakecentral.com/recipes/14979/peanut-butter-dream-buttercream

I use the peanut butter buttercream recipe on the wilton site, but I replace the milk with heavy cream and whip it.... YUMMY!!

The next time you make buttercream, set a little aside and just peanut butter.

I've used that before and it turned out great.