You can get the recipes for these peanut butter truffle cupcakes by Nicky at A Good Table! They look amazing and she writes:
As for the cupcakes, Yummm. The cupcake was a regular enough chocolate but the truffle inside made them so much more awesome. I think I may have eaten one or two of the truffles all by themselves before putting the rest into the cupcakes. The frosting was so yummy and I could just sit and eat it alone also. Bad me!