01 - Arrange popped popcorn in a large bowl, discarding any unpopped kernels.
02 - Add roasted peanuts to the popcorn and gently mix to distribute evenly.
03 - Place sugar, butter, corn syrup, and salt in a heavy-bottomed saucepan. Cook over medium heat, stirring constantly, until butter is melted and mixture is combined.
04 - Increase heat to medium-high and allow mixture to boil for 4 to 5 minutes without stirring, until it reaches a golden color. Remove from heat, stir in baking soda and vanilla extract until thoroughly blended.
05 - Immediately pour hot caramel over popcorn-peanut mixture. Use a spatula to mix and evenly coat all pieces before caramel sets.
06 - Drop coated mixture by heaping tablespoons onto waxed paper or parchment-lined trays, spacing to keep clusters separate.
07 - Allow clusters to cool completely at room temperature for at least 30 minutes until firm.