In a medium sauce pan over medium heat melt 1 cup butter with 2 packed cups of brown sugar and a half cup of light corn syrup. Once combined and it starts to boil DO NOT STIR for 5 minutes. Also do not be impatient like me and crank the heat up to get it to boil. That's how you burn it. And it ends up in sticky clumps on your popcorn instead of coating it.
After 5 minutes are up remove from the heat and stir in the baking soda. Your Carmel will poof up even more than it did before feel free to give it a minute before you start pouring it over the popcorn.
In a huge bowl begin to drizzle the Carmel over the popcorn turn with a large spoon or spatula gently and often to get as even a coat as possible without breaking up the pieces (this is the part I find most daunting its just so big and it takes a lot of arm strength to hold the pot up while stirring with your other hand)
Once combined spread on to baking sheets (should fill two evenly) Bake in the oven at 250 degrees for 1 hour turning every 15 minutes. This will help it coat even more along with creating a nice crunch of Carmel on the outside vs being chewy.
Voila! There you have it. Beautiful sweet crunchy Carmel corn! This batch makes 15 - 20 (depending on size and how much you fill them) individual party bags should you want to hand it out to friends or coworkers. Or if you want to enjoy a whole massive bowl to yourself....I won't judge you! In zip lock bags it usually stays pretty fresh for about a week and a half (sometimes longer if not opened regularly. My mom sent me a batch to Australia for my birthday 2 years ago and it made the almost 2 week shipping trip in great shape!). Enjoy!