(For use in Monster Mix)
Combine the first three ingredients in a medium saucepan and melt over medium heat, stirring constantly until mixture is caramelized and reaches an amber color or reaches hard-crack stage. Remove mixture from heat and stir in vanilla. Pour over popped popcorn and stir until popcorn is completely coated. (CAUTION! Syrup mixture will be VERY hot. Do not touch!) Spread popcorn on baking sheet and let cool until hardened.