Caramel Corn - brown sugar

Ingredients

• 2 cups brown sugar
• 1 cup margarine
• 1/2 cup light corn syrup
• 1 tsp salt
• 1 tsp baking soda
• 1 tsp vanilla
• 6 quarts popped popcorn (Nancy says to use stove popped - not air-popped or microwaved, but I use three bags of light butter flavored microwave popcorn, and it works fine)