Prepare Baking Sheet: Line a large baking sheet with wax paper. This will prevent the popcorn mixture from sticking.

Combine Popcorn and Cereal: In a large bowl, combine the plain popcorn and Lucky Charms cereal. Set aside.

Melt Butter: In a medium saucepan over medium heat, melt the butter until completely melted.

Melt Marshmallows: Add the mini marshmallows to the melted butter and stir constantly until completely melted and smooth. Remove from heat as soon as the marshmallows are melted to prevent burning.

Coat Popcorn Mixture: Pour the melted marshmallow mixture over the popcorn and cereal mixture in the large bowl. Use a spatula or large spoon to fold everything together until it’s evenly coated.

Spread on Baking Sheet: Pour the coated popcorn and cereal mixture onto the prepared baking sheet. Spread it out in an even layer.

Add Toppings: Immediately sprinkle the mint M&M’s® and sprinkles over the top of the popcorn mixture.

Cool and Break Apart: Allow the popcorn mixture to cool and dry completely. This will allow the marshmallow coating to set. Once it’s set, break it into pieces.

Serve Break into pieces and enjoy!