Boil 5 minutes:

2 c. brown sugar
2 sticks butter
1/2 c. corn syrup
1 tsp. vanilla, optional

Remove from heat and add:

1 tsp. salt
1 tsp. baking soda

Stir and mix well into 8 to 10 quarts popped corn. Put into large roasting pan. Place in oven 1 hour at 200 degrees. Stir every 10 minutes. Cool; store in tightly covered container to keep crisp.