Preheat oven to 250°.
Coat an extra large mixing bowl lightly with cooking spray and place popcorn and peanuts in bowl.
Melt butter over medium heat in a large saucepan. Stir in brown sugar, corn syrup, molasses, and salt.
Bring to a boil over medium heat, stirring constantly.
Boil for five minutes, stirring occasionally. Remove from heat and stir in vanilla.
Pour mixture over popcorn and peanuts and stir with a silicone spoon or spatula lightly coated with cooking spray, until well coated. Don't worry if some pieces are more coated with the caramel than others, as the caramel will loosen as it bakes in the oven.
Pour into two lightly greased baking sheets. Bake at 250° for 45 minutes, stirring and rotating the pans every 10 minutes. Cool completely. Store in airtight containers.