Place all 16 cups of popped popcorn in a large bowl
Set aside a large baking sheet
Pre heat Oven to 250°
In a medium saucepan combine brown sugar, corn syrup, and butter and bring to a boil. Boil for 5 minutes, stirring constantly
Add vanilla and baking soda and mix well. Mixture should be foamy.
Pour over popcorn
Stir well to coat the popcorn in the caramel mixture
Pour popcorn onto prepared pan and place in oven for 45 minutes
Gently stir/mix popcorn around every 15 minutes
Allow to cool and then store in an airtight container
