When you need a sweet, salty, crunchy snack that everyone loves, homemade caramel popcorn is the answer! It’s easy to make and has a rich caramel flavor that’s full of depth – plus a little saltiness for the perfect balance. Bake the popcorn low-and-slow at 250°F for about an hour. This is a snack you won’t be able to stop grazin’ on, whether it’s movie night or not!
Prepare a large rimmed baking sheet (or two) with parchment paper. Preheat the oven to 250F, and begin making the popcorn. If using already made, unbuttered popcorn, skip to step 5.
In a large heavy-bottomed large stockpot or dutch oven, add the oil and three popcorn kernels, heating over high heat. Cover the pan. These are the "test kernels" and once they pop, it signals that the oil is officially hot enough to pop all the kernels at the same time.
Meanwhile, measure out the remaining 1/2 cup of popcorn kernels. Once the three test kernels have popped, immediately add the 1/2 cup of popcorn kernels to the pan. Cover and remove from heat, gently swirling from side to side for 20 seconds. Return the pan to the heat, and the popcorn kernels will almost immediately begin popping.
If needed, you can gently shake the pan side to side to allow any remaining kernels to make it to the bottom of the pan to pop, but don't remove it from the heat. Once the popping has slowed or just stopped, pour the popcorn into a large mixing bowl.
In a small saucepan, whisk together brown sugar, maple syrup, corn syrup, and salt. Bring to a simmer and let the mixture simmer, without stirring, for 4-5 minutes. Remove from heat and whisk in small cubes of butter, vanilla extract, and baking soda. The mixture will foam up, but just keep whisking.
Pour the caramel mixture over popcorn while stirring it, if possible. Work quickly, as it will be sticky, and stir to coat. Then transfer the popcorn to the baking sheet and spread it in a single layer. Bake for 1 hour to an 1 hour and 15 minutes, stirring in 15-minute increments to ensure no spots burn and the popcorn is evenly coated.
Let the popcorn cool, then transfer to store in an airtight container at room temperature for 5-7 days.