In a large pot with a lid, heat about 2 tablespoons of oil over medium heat. Add the popcorn kernels, cover the pot, and shake it occasionally until popping slows down. Once popped, transfer to a large bowl and set aside.
In the same pot, over medium heat, add the chopped pecans and toast them for about 3-4 minutes, stirring frequently, until they are golden and fragrant. Be careful not to burn them. Remove and set aside.
In the pot, reduce the heat to medium-low and add butter, brown sugar, cinnamon, and salt. Stir continuously until the mixture is smooth and comes to a gentle boil. Allow to boil for about 2 minutes without stirring.
Remove the pot from heat and quickly stir in the baking soda and vanilla extract until well combined. The mixture will bubble and expand.
Immediately pour the caramel sauce over the popped popcorn and toasted pecans. Use a spatula or wooden spoon to gently mix until all popcorn is evenly coated.
Spread the popcorn mixture onto a parchment-lined baking sheet, using your hands or spatula to break up any large clumps and spread it out evenly. Allow to cool for about 20-30 minutes.
Once cool, break into pieces and serve in a large bowl or individual bags for a snack.
Notes
Allow the popcorn to cool completely before breaking into pieces for the best texture.