Cook butter, brown sugar, salt and syrup in a glass bowl on high power in microwave for 2 minutes. Remove and stir. Cook for 2 more minutes on high.
Add soda and stir. Pour over puff corn in paper sack and stir to cover each kernel.
Put puff corn mixture in the microwave and cook on high for 1 1/2 minutes.
Take puff corn out and stir again in the bag. Put back in microwave and cook for another 1 1/2 minutes.
Remove puff corn from sack and spread on cookie sheet to cool.
NOTE: Regular popcorn can be substituted for the puff corn. You should have enough popped corn to fill 1/2 paper sack.