Line an 8x8-inch square baking pan or a 9x9-inch square baking pan with aluminum foil and spray with non-stick spray.
Crush the graham crackers in a food processor. You want them broken up into small pieces but not into a powder. Chop peanuts. It really depends on what size you like, but I like to leave them chunky for texture.
In a large bowl, mix all the ingredients except the powdered sugar until they're well combined. The dough will be thick.
Dump the mixture into your prepared pan and press down. Smooth the top flat.
Chill for 30 minutes to 2 hours.
Remove the bars from the refrigerator.
Put the powdered sugar in a mesh strainer like this and sprinkle over the top of the bars. With a sharp knife, cut into squares. Serve.
Store in an airtight container. They'll be fresh for up to one week.