Making crunchy caramel popcorn is a two step process. First you make a simple caramel sauce on the stovetop by boiling butter and brown sugar for a few minutes. Then you coat the popcorn with caramel sauce and bake it in the oven until dry and crispy. The whole process takes a little over an hour, and keeps well in sealed containers for several days.
Ingredients
1/2 cup unpopped corn kernels (10-12 cups popped)
1 tablespoon vegetable oil
3/4 cup (1 1/2 sticks) unsalted butter
1 cup packed brown sugar
1 teaspoon vanilla extract
1/2 teaspoon kosher salt
1/4 teaspoon baking soda
Instructions
Arrange two oven racks in the top and bottom third of the oven and preheat the oven to 250°F. Line two baking sheets with parchment. Once you start making the caramel sauce, everything comes together quickly so have all the ingredients and equipment you need handy.
Make the popcorn. Warm 3 corn kernels and the oil in a large lidded saucepan over medium heat. When the kernels pop, add the rest of the corn kernels to the pan, shake to coat with oil, and put the lid on the pan. Pop the corn, shaking the pan occasionally, until the popping slows. Empty the popped corn immediately into a large heat-proof bowl. This makes about 10 cups of popcorn; make the popcorn in two batches if your pan is not large enough.
Make the caramel sauce. Melt the butter in a 2-quart saucepan over medium heat. Mix in the sugar until the sugar is completely moistened. Increase the heat to medium high and bring the mixture to a boil. Once boiling, boil for 3-4 minutes while stirring and scraping the bottom of the pan continuously. (Boil for a minute less if cooking on an electric stove.) The exact cooking temperature isn’t critical with this recipe, but ideally you want the sugar mixture to reach between 250°F and 300°F. The longer you cook the syrup, the crunchier it will be. For very crunchy popcorn, stop cooking when you see the first wisps of smoke coming from the sugar mixture.
Off the heat, add the vanilla, salt and baking soda, and stir until combined. The sugar mixture will bubble up violently. Continue stirring until you form a thick, glossy sauce.
Combine the caramel sauce and popcorn. Slowly pour the caramel sauce over the popcorn while stirring the popcorn (it helps if you have a partner for this step — one person pouring while the other stirs the popcorn). Continue stirring the sauce into the popcorn until all of the kernels are coated.
Bake the caramel popcorn. Divide the popcorn between two baking sheets, spreading the popcorn out into an even layer. It’s ok if the popcorn clumps together. Bake for one hour, stirring every 15 minutes and breaking up any clumps.
Let the popcorn cool completely on the baking sheets. Serve immediately or store in an airtight container for up to a week.