Pop your popcorn; either 3 bags of microwave popcorn or you can pop the equivalent of 3 bags in an air popper or on the stove (the measurement doesn’t have to be exact!) Pull out any un-popped kernels.
Melt butter in a large stockpot over medium-high heat.
Stir in brown sugar, corn syrup and salt. Cook until nice and smooth and until there is no layer of butter sitting on top.
Add in vanilla, then add the baking soda. The baking soda will cause it to fluff up slightly, so make sure to use a tall stockpot!
Pour over your popped popcorn in a large bowl, or you can add your popcorn into the stockpot. Either way, make sure you bowl/pot is large enough to mix through.
Serve and enjoy! You can save it and it will stay good for a few days; just put a lid on your bowl!
