Pulse the graham crackers in a food processor until they are crumbs. Or place them in a ziplock bag and beat with a rolling pin. Set aside.
In the bowl of an electric mixer or in a large bowl with a hand-held mixer, beat together the butter and peanut butter until smooth. Add the powdered sugar and beat on high until light and fluffy, about 2 minutes.
Add the graham crackers and mix to combine. At first mixture will be very thick, but keep beating on medium high speed until it lightens and starts to stick to the sides of the bowl.
Dump contents into a quarter-sheet pan or 9x13-inch pan lined with parchment paper and press into the pan evenly, using greased fingers or a greased spatula (I actually like to use the paper wrappers from the butter, they are perfect for a job like this.)
In a double boiler over barely simmering water, melt the chocolate chips, stirring until smooth. Remove from heat and pour on top of peanut butter mixture. Use a spatula to spread evenly. Sprinkle with salt, if desired.
Chill in the fridge for 1-2 hours until set. Slice and serve. For best results, store in the fridge.
Video
Notes
NOTES
Not natural-style peanut butter will work best for these bars. You can use natural style if you'd like, but the bars will be much softer.