Pour the popped popcorn into a bowl, sifting through to remove any unpopped kernels.
8 cups popped popcorn
In a small saucepan, melt the butter.
½ cup butter
Add the brown sugar and corn syrup and stir until the mixture begins to bubble.
1 cup brown sugar, 1 Tablespoon corn syrup
Add the marshmallows and stir until melted and smooth.
1-½ cups mini marshmallows
Pour the caramel mixture over the popcorn and stir to coat.
Pour the popcorn onto a large baking sheet to cool.
Allow the popcorn to cool before serving.