Pop the Popcorn: Place the popcorn kernels in a microwave-safe bowl, cover it, and microwave until the popping slows down to about 2 seconds between pops.
Prepare the Caramel Sauce: In a separate bowl, melt the butter and mix in brown sugar, corn syrup, and salt. Microwave until the mixture is bubbling, stirring occasionally.
Combine Popcorn and Caramel: Pour the caramel sauce over the popped popcorn and gently stir to coat evenly.
Microwave Again: Microwave the caramel-coated popcorn for another 1-2 minutes to ensure the caramel is evenly distributed.
Add Vanilla and Baking Soda: Stir in the vanilla extract and baking soda, giving the popcorn a delightful flavor and a light, airy texture.
Spread and Cool: Spread the caramel popcorn on a parchment-lined baking sheet to cool and set.