Caramel Corn in the Microwave

I found this recipe online - didn't save the source - but have had 2 people now ask me for the recipe.

Spray the inside of a large brown paper grocery bag* with Pam.  Place 14 cups popped corn in the bag. Salt to taste.  Set aside.

Combine:
1 C brown sugar
1/4 C light corn syrup
1/2 t baking soda
1/2 C (1 stick butter)

Cook mixture over medium heat for 2-3 minutes until mixture is bubbly.  Don't overcook.  Pour over popcorn in bag.  Fold bag top down and microwave on high for 1 minute.  Remove bag.  Shake well.  Microwave another 1 minute.  Shake.  Empty popcorn onto large cookie sheet covered with waxed paper to cool.

*I ran out of brown bags, so I just made it in a giant plastic container with successful results.