Place the popcorn in a large bowl and then set aside.
Melt the butter in a saucepan over medium high heat. Stir in the granulated sugar, vanilla extract, ground cinnamon and salt. Stir and cook until the mixture is thick and bubbly.
Pour the mixture over the popcorn and stir to coat the popcorn in the mixture.
Place the coated popcorn on baking sheets lined with parchment paper. Bake for 10-15 minutes, stirring the popcorn every 3-4 minutes.
Turn the oven off and let the popcorn sit in the oven for 20 minutes. The popcorn will get crispy as it sets.
Remove from the oven and let cool. Then the popcorn is ready to serve and enjoy!
Notes
Store the leftovers in an airtight container at room temperature for up to 1 week.