Oh, and butter (EB, of course) your pan and press a sheet of parchment paper down on top of the butter. Makes it much easier to take the whole thing out of the pan and cut!
Just wanted to add that if you can get your hands on vegan white chocolate chips they are even better! For some reason the white chocolate really complements the peanut butter! ;)b
Solalia: Try a no stir peanut butter. There is no additional oil in the recipe and you can always add a little extra flour so the dough is at the right consistency.
"Peanut Butter Cup" Bars