1. Place the popped popcorn onto a large greased baking pan with sides like a cookie sheet or roasting pan. Add the peanuts to the popped corn if using. Set aside.

2. Preheat the oven to 200 degrees. Combine the brown sugar, corn syrup, butter 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.

3.. 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 pans, and stir to coat. Don't worry about the popcorn not being coated at this point.

4. Bake for 45 minutes, removing the pans, and giving them each a good stir every 15 minutes. Line the counter top with waxed paper. Dump the corn out onto the waxed paper and separate the pieces. Allow to cool completely, then store in airtight containers or resealable bags.