Caramel Popcorn with Marshmallow

Caramel Popcorn with Marshmallow 2 cups brown sugar 1 teaspoon vanilla extract 23 large marshmallows 2 (3.5 ounce) packages microwave popcorn, popped 1/4 cup light corn syrup (such as Karo®) 1 cup butter Cook 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. Put the popcorn in a large bowl; pour the marshmallow mixture over the popcorn and gently stir with a big spoon to coat.