Preheat your oven to 400 degrees.
Add 1 cup of chocolate chips and 1 cup of peanut butter chips to a cast iron skillet.
I added 2 tsp of Vanilla and stirred the chips to even them out in the skillet.
Top the chips with marshmallows.
Bake in the oven for about 8 minutes.
Marshmallows should be brown and melted.
The original recipe said to bake at 450. I did that and the marshmallows were brown at 4 minutes and not quite gooey enough. I turned off the heat and left it in the oven a few more minutes and this was perfection.
The vanilla was not part of the original recipe, but it was a great addition.