In an air popper or in a pot on the stove, pop 1/2 cup of white popcorn kernels according to directions on the container.
Pour the popcorn out onto a baking sheet and set aside. Now make the salted caramel.
In a sauce pot over medium-high heat, melt the butter. Add the brown sugar and karo syrup. Using a rubber spatula, stir constantly. Bring to a boil and let it boil for one minute, while stirring constantly.
Add the sweetened condensed milk and stir constantly. Let it boil for 2 minutes. Continue to stir. After 2 minutes, add the vanilla and the salt. Continue to cook and stir for one more minute.
Remove the caramel from the heat. Do not overcook, the sugar will burn and harden if overcooked.
Pour the caramel overtop of the popcorn, using as little or as much as you like. Stir until the popcorn is coated in the caramel.
You can eat the salted caramel popcorn right now as is- it will be soft and stick and the popcorn will loose a little bit of its crunch, but it’s delicious.
Or you can make a crunchy caramel popcorn by following these instructions- Preheat your oven to 200 degrees. Line a baking sheet with parchment paper. Pour the salted caramel popcorn onto the baking sheet, spreading it out as much as you can. Bake for one hour, stirring every 15 minutes (and separating out the popcorn). Let it cool on the baking sheet before serving. Enjoy!