1 cup butter or margarine
2 cups firmly packed brown sugar
1/2 cup light or dark corn syrup
1 teaspoon salt
1/2 teaspoon baking soda
1 teaspoon vanilla extract
6 quarts popped popcorn, unsalted

Melt butter. Stir in brown sugar, corn syrup and salt. Bring to a boil, stirring constantly. Boil without stirring for 5 minutes.

Remove from heat. Stir in baking soda and vanilla extract. Gradually pour over popped corn, mixing well. Turn into 2 large shallow baking pans. Bake at 250 degrees F for 1 hour, stirring every 15 minutes.

Remove from oven; cool completely. Break apart.

Makes about 5 quarts.