Preheat your oven to 350 degrees F. Line a square baking pan with parchment paper, making sure there are flaps of parchment paper sticking over the edges for easy removal of the cookie. I didn't butter my pan since the cookie base was going to be pretty buttery and I didn't have any problems removing it.
Beat the butter and both sugars together until fluffy. Add in the peanut butter and egg, mix to combine. Scrape down the sides of the bowl and add the salt, baking soda and vanilla. Mix to combine. Add in the flour and mix until blended. Stir in the chopped peanuts and Nutter Butters.
Place 2/3 of the cookie dough into the pan and press into an even layer. Pour the jam over top and smooth into an even layer. Drop the remaining cookie dough overtop in rough dollops. You can top with more peanuts if desired.
Bake for approximately 45 minutes, until the cookie is golden in colour. Allow the cookie to cool and stiffen in the pan, approximately 20 minutes. When the cookie is solid enough, lift it out of the pan and let it continue cooling on a rack. Make sure it's completely cool before attempting to slice.