Rum-raisin popcorn

1. In a heavy saucepan, combine brown sugar, corn syrup, and butter.
2. Place over med-high heat.
3. Cook, stirring often until sugar dissolves.
4. Continue to boil gently, without stirring, until a candy thermometer reaches 280°F (syrup separates into hard, but not brittle, threads when dropped into very cold water).
5. Remove from heat and stir in rum extract.
6. Pour over popcorn and raisins.
7. Spread out evenly on a lightly buttered cookie sheet.
8. Cool and break into small pieces.