6 qt. Unseasoned popped popcorn 2 cup Brown sugar 1/2 cup Light corn syrup 2 Sticks butter 1 tsp. Salt 1/4 tsp. Cream of tartar 1 tsp. Baking soda
Preheat over to 200 degrees F. Divide the popcorn between two large bowls. Oil 2 lipped cookie sheets very well and set aside. In a deep saucepan, combine brown sugar, corn syrup, butter, salt and cream of tartar. Insert candy thermometer. Bring to a boil and cook the mixture over medium heat for about 5 min, stirring occasionally, until the thermometer registers 260 degrees F.(hard ball stage). Remove from the heat and quickly stir in baking soda. The mixture will foams.
Pour the syrup mixture over the popcorn, half into each bowl. Work quickly to coat all the popcorn with the caramel. Spread popcorn evenly on the cookie sheets and bake for 1 hour, stirring 3 times. Remove from oven and spread popcorn on wax paper to cool, breaking up the larger pieces, if necessary. Store in airtight container.