In a stand mixer beat the butter, peanut butter, and sugar scraping down the sides.
Add the egg and vanilla and mix well.
Add the flour, graham crackers, salt and baking soda. Mix well.
Stir in the chocolate chunks and marshmallows.
Pour into a greased 9x9 pan and press until even.
Bake about 20 minutes or until cooked through.
Notes
Feel free to use smooth peanut butter if you prefer. If you are gluten-free you can replace the all-purpose flour with an all-purpose gluten-free flour.