Preheat the oven to 250 degrees F (95 degrees C). Place popped popcorn in a very large bowl.
Melt the butter in a large saucepan over medium heat. Stir in the sugar, salt and pumpkin pie spice. Cook, stirring constantly, until the sugar is dissolved (3-4 minutes).
Remove from the heat and then stir in the vanilla extract.
Then pour the sauce over the popcorn and stir it to coat all the popcorn with the butter mixture.
Then place the popcorn in two large shallow baking dishes/ or pans and bake in a preheated oven, for approximately 20-25 minutes (stirring every 5 minutes).
Remove from the oven and let cool completely before breaking into pieces.
Then the pumpkin is ready to serve and enjoy!
Notes
Store the leftovers in an airtight container at room temperature for 1-2 weeks.