Make Brownie Mix as directed on box.
Pour into greased 9x13 pan. Set aside.
In a medium bowl mix together peanut butter, powdered sugar and vanilla.
Drop by spoonfuls into brownie mix. Use a knife to swirl it into the mix.
Put in oven, cook until halfway point. Remove and add caramel chips by sprinkling them on top.
Return to oven to finish cooking brownies. Just before done, about last two minutes. Remove and sprinkle marshmallows on top. Cook until they are melted slightly and golden brown. Let cool a few minutes before enjoying.
We love these brownies warm.