1Cook and stir the marshmallows, brown sugar, corn syrup, butter, and vanilla extract together in a pot over medium-low heat until the marshmallows are completely melted, 5 to 7 minutes.
2Put the popcorn in a large bowl; pour the marshmallow mixture over the popcorn and gently stir with a big spoon to coat.
Footnotes
Tip
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.