1. Make the brownies according to directions and add the chocolate chips.
2. Place in a greased 9x13" pan.
3. Bake 5 minutes short for the time on the box, then remove from the oven, cover with marshmallows and bake for another couple minutes.
4. Remove from the oven and sprinkle with reese's and allow to cool for 2 to 5 minutes before serving.