Start by preparing about 12 cups of fresh popcorn using your preferred method—either air-popped or stovetop.

In a medium saucepan over medium heat, combine unsalted butter, marshmallows, and high-quality caramel sauce. Stir continuously until melted and thickened into smooth caramel—about 5-7 minutes.

Carefully pour the warm caramel mixture over the bowl of popcorn, ensuring even coverage. Gently mix with a spatula or wooden spoon until well coated.

Fold in your favorite mix-ins like nuts, chocolate chips, or crushed pretzels while the caramel is still warm.

Preheat your oven to 250°F (120°C) and line a baking sheet with parchment paper. Spread the caramel-coated popcorn in an even layer. Bake for 30-35 minutes, stirring every 10-15 minutes.

Remove from the oven and allow to cool completely. Once cooled, break into pieces and serve.