Line a 9x9 square pan with two sheets of parchment paper, making sure the parchment extends over the sides of the pan to form a "sling". Secure the sides with binder clips if you would like.
In a large pot over medium low heat, cook the butter until it is a deep golden brown color and smells nutty and toasted, about 5 -7 minutes. Turn off the heat.
½ cup butter, unsalted or salted
Whisk in the peanut butter until smooth.
½ cup peanut butter
Stir in the marshmallows until smooth. If there are marshmallows that haven't fully melted, place the pot back over low heat and stir until melted. Turn off the heat.
6 cups mini marshmallows
Stir in the Rice Krispies, stirring until fully coated.
6 cups Rice Krispies cereal
Press the mixture into the prepared pan with the bottom of a glass or measuring cup.
In a medium bowl, combine the chocolate and peanut butter. Melt in 30 second increments, stirring after each, until smooth and melted.
1 ½ cup semi sweet chocolate chips, ⅓ cup peanut butter
Spread the chocolate peanut butter mixture over the treats, using an offset spatula.
Create shallow swirls in the chocolate with the spatula or with a toothpick.
Sprinkle the peanuts over the chocolate.
¼ cup peanuts, finely chopped (optional)
Refrigerate the treats for 20 minutes so that the chocolate peanut butter can set a bit before serving.
Remove the treats from the pan with the parchment "handles". Cut into 16 squares and serve.