In a pan combine
butter, corn syrup, and brown sugar, stirring as it melts together.
Bring to a boil while continuing to stir and boil for one (1)
minute. Remove from heat and add vanilla.
Pour sugar
mixture over popped corn mixture and stir to coat.
Bake at 350°
for 15-20 minutes. Remove from oven and spread over wax paper
to cool. Store in an air-tight container.