In a large bowl, mix together the peanut butter, powdered sugar, heavy cream, and vanilla extract.
Mix until a smooth dough forms.
Pour the dough onto parchment paper and roll into a log then refrigerate for 30-minutes.
Slice into 1/2" rounds and dip into additional powdered sugar if desired.
Wrap leftovers in parchment paper or plastic wrap and refrigerate for up to 10 days.