Preheat your oven to 250°F (120°C). Line a baking sheet with parchment paper or a silicone baking mat and set aside
In a large mixing bowl, place the popped popcorn and set aside
In a large saucepan over medium heat, combine the brown sugar, cannabis-infused butter, light corn syrup, and salt. Stirring constantly, bring the mixture to a boil
Once the mixture reaches a boil, continue stirring and let it boil for 4-5 minutes without stirring. The mixture should reach the soft-ball stage, or about 235°F (113°C) on a candy thermometer
Remove the saucepan from the heat and quickly stir in the baking soda and vanilla extract. Be careful as the mixture will bubble up
Immediately pour the hot caramel mixture over the popped popcorn in the mixing bowl. Use a wooden spoon or heatproof spatula to gently toss and coat the popcorn evenly with the caramel
Spread the caramel-coated popcorn evenly onto the prepared baking sheet
Bake the popcorn in the preheated oven for 45 minutes, stirring every 15 minutes to ensure even coating and prevent burning
Once baked, remove the caramel popcorn from the oven and let it cool completely on the baking sheet
Once cooled, break the caramel popcorn into clusters and serve immediately, or store in an airtight container for up to one week