adapted from Sugar Cooking
7 quarts plain popped popcorn
2 cups dry roasted peanuts (optional)
2 cups brown sugar
1/2 cup light corn syrup
1 teaspoon salt
1 cup margarine
1/2 teaspoon baking soda
1 teaspoon vanilla extract
Line 2 large baking sheets with parchment paper. Preheat the oven to 250 degrees F.Make popcorn and place in a very large bowl or pot (or 2 large bowls). It can also be mixed in a large doubled paper bag.
Combine the brown sugar, corn syrup, margarine and salt in a saucepan. Bring to a boil over medium heat, stirring enough to blend. Once the mixture begins to boil, boil for 5 minutes while stirring constantly. Remove from the heat, and stir in the baking soda and vanilla. The mixture will be light and foamy. Immediately pour over the popcorn in the bowls or bag. Stir to coat.
Bake for 1 hour, removing the pans, and stirring well every 15 minutes. After it has baked separate into pieces if need. Allow to cool completely, then store in airtight containers or resealable bags.