In a heavy saucepan, combine brown sugar, corn syrup, water, butter and pumpkin
pie spice. Bring to a boil, stirring until sugar is dissolved. Reduce heat and gently
boil, stirring occasionally, until a candy thermometer reaches 285 degrees F (syrup
separates into hard, but not brittle, threads when dropped into very cold water).
Gradually pour over popcorn, tossing to coat evenly.