Preheat oven to 350 F.
Spread butter on a 12” cast iron skillet.
Spread chocolate chip cookie dough in the skillet.
Bake at 350 F for 20 minutes (or until cooked through).
Spread creamy peanut butter on top of baked cookie.
Add marshmallows.
Broil until perfectly roasted.
Drizzle with melted peanut butter.