1Heat oven to 250F. Place puffed popcorn curls an a very large bowl.
2In large sauce pan, combine brown sugar, corn syrup & butter; bring to a boil over medium heat, stirring constantly. Simmer 2 minutes, remove from heat. Stir in baking soda. Pour mixture evenly over popcorn; mix well.
3Place contents into a large roaster in 250F oven. Stirring in 3- 15 minute intervals.
4Pour prepared popcorn on large baking sheet covered with either wax paper or parchment paper. Allow to cool. Store in airtight container.