Preparation Time: 10 minutes
Have your 4 quarts of popped corn ready. Put butter, brown sugar, and salt into a large microwavable bowl and bring to a rolling boil (using highest power). Add soda and stir well. Put popped corn into a large brown paper bag. Pour mixture over popcorn. Stir and shake well. Place bag into microwave oven and microwave for 1 1/2 minutes. Shake bag well and then cook for another 1 1/2 minutes. Pour out onto cookie sheets to cool.
May add a few drops of your favorite food color for special occasions or just because.