Preheat oven to 350°
Baking sheets should be greased or lined with parchment paper.
In a small microwave-safe bowl, combine 6 tbsp of chocolate chips and the butter. Microwave on medium for one minute, stirring halfway through until melted. Stir until smooth, set aside to cool.
In a small bowl, whisk together flour and baking soda and set aside.
In a medium bowl, using a wooden spoon, beat together the egg yolk and the brown sugar until smooth.
Stir in cooled melted chocolate. Gradually add flour mixture stirring well.
Stir in peanuts, peanut butter chips, and remaining 3 tbsp of chocolate chips, until well combined.
Drop dough by heaping teaspoonfuls spacing them about 2 inches apart on prepared baking sheet.
Bake in preheated oven for 9 - 13 minutes or until set around the edges, but slightly soft in the center.
Let cool for 5 minutes on sheet, then transfer to wire rack to cool completely.