Using an air popper, pop popcorn kernels into a large bowl and set aside. Line a baking sheet with parchment paper and preheat oven to 250°F.

In a large saucepan, melt together butter, brown sugar, and corn syrup, whisking to combine. Carefully bring to a boil and cook for 1-2 minutes.

Remove from heat and whisk in vanilla, 1/2 teaspoon smoked salt, and baking soda. Be careful, as the mixture will bubble!

Pour caramel over popcorn and stir quickly but gently to combine. Spread popcorn onto prepared baking sheet.

Bake for 10-15 minutes, then remove and sprinkle on remaining smoked salt. Let cool completely before breaking into pieces and eating or storing.

Store leftover caramel corn in an airtight container in the freezer. Bring to room temperature before enjoying.