5 qts. popped popcorn
4 tbsp. butter
1 c. packed brown sugar
1/2 c. light corn syrup
2/3 c. sweetened condensed milk (not evaporated)
1/2 tsp. vanilla

Melt butter in a 2 quart pan; stir in sugar and syrup. Bring to boiling over medium heat. Stir in condensed milk. Boil gently, stirring constantly until mixture reaches soft ball stage, about 15 to 20 minutes. Stir in vanilla. Pour over popcorn. Mix well, shape into balls.