Step 1

Preheat the oven to 250 degrees Fahrenheit. Place popped popcorn in a very large bowl.

Step 2

Heat a saucepan over medium heat. Melt the butter and stir in brown sugar, corn syrup, and salt. Bring mixture to a boil, stirring continuously until the sugar is dissolved. Allow it to boil without stirring for 4 minutes.

Step 3

Turn off the heat and mix in the vanilla and baking soda. Expect the caramel to foam up once the baking soda is added.

Step 4

Pour the caramel in a thin stream over the popcorn. Stir while pouring and until the caramel coats the popcorn evenly.

Step 5

Place the popcorn in a single layer into 2 large shallow baking dishes. Bake for 1 hour, stirring every 15 minutes. Cool completely, about 5 minutes, and break into pieces. Serve and enjoy!