Pop the popcorn using your preferred method. Remove all unpopped kernels (this matters more than people admit).Place popcorn in a very large heatproof bowl.
In a medium saucepan over medium heat, combine: brown sugar, butter, corn syrup, salt. Bring to a gentle boil, stirring constantly. Once boiling, stop stirring and let it boil for 4 minutes.
Remove from heat. Quickly stir in: baking soda (it will foam — that’s normal), vanilla extract
Immediately pour caramel over popcorn.Stir gently but thoroughly until evenly coated.
Preheat oven to 250°F (120°C). Spread caramel popcorn evenly onto two parchment-lined baking sheets. Bake for 45 minutes, stirring every 15 minutes. This step is what gives you crisp, non-sticky popcorn.
Remove from oven and let cool completely. Break into clusters once fully cooled.
