Step 1

Place popped popcorn in a large brown paper bag.

Step 2

Add the butter to a medium microwave safe bowl and microwave for 2 minutes. Stir in the brown sugar, corn syrup, and salt.

Step 3

Microwave on high for 3 minutes, stopping to stir every minute.

Step 4

Working quickly stir in baking soda and vanilla. Pour the caramel mixture into the bag with the popcorn. Close the bag and shake well.

Step 5

Add the brown bag to the microwave and microwave for 1 minute and shake. Repeat this step two more times.

Step 6

Pour the popcorn onto wax paper and spread out to cool.

Step 7

Store cooled popcorn in a sealed container.