Movie night treat: Marshmallow Caramel Popcorn. 1/2 c. brown sugar 1/2 c. butter 9-10 marshmallows 12 c. popcorn. Microwave brown sugar and butter for 2 minutes. Add marshmallows. Microwave until melted, 1 1/2 to 2 minutes. Pour over popcorn. Definitely going to try this on the stovetop instead of microwave.