Place the popped popcorn into a large brown paper bag. Set aside. In a 2-quart casserole dish, or other heatproof glass dish, combine the brown sugar, butter, corn syrup, vanilla extract and salt. Heat at full power for 3 minutes in the microwave, then take out and stir until well blended. Return to the microwave, and cook for 1 minute and 30 seconds more. Remove from the microwave, and stir in the baking soda. Pour the syrup mixture over the popcorn in the bag. Roll down the top once or twice to close the bag, and shake to coat the popcorn. Place bag into the microwave, and cook for 1 minute 10 seconds. Remove, shake, flip the bag over and return it to the microwave. Cook for another 1 minute and 10 seconds. Dump the popcorn out onto waxed paper, and let cool until coating is set. Serve immediately or store in an airtight container.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.