01 -
Pop the popcorn using an air popper, stovetop, or microwave, then place in a large bowl, discarding any unpopped kernels.
02 -
Melt butter in a large saucepan over medium heat. Add brown sugar and corn syrup, stirring until sugar dissolves and mixture is uniform.
03 -
Lower heat to medium-low and add the marshmallows. Stir continuously until fully melted and the mixture is smooth.
04 -
Remove saucepan from heat and immediately stir in vanilla extract.
05 -
Pour the hot caramel-marshmallow mixture over the popcorn. Gently fold until all kernels are evenly coated.
06 -
Spread coated popcorn onto a large, foil-lined baking sheet lightly sprayed with non-stick cooking spray. Allow to cool and set for 10–15 minutes.
07 -
Once cooled, break into clusters and serve. Store leftovers in an airtight container.