Place the butter and 3 cups of the mini marshmallows in a microwave safe bowl.  Heat in 30 second intervals, stirring after each interval until the marshmallows and butter are melted and combined.

Then add in the green gel food coloring until the mixture in a bright green color like the Grinch.

Place the popcorn in a large bowl and pour approximately half of the marshmallow mixture onto the popcorn.  Gently toss the popcorn to coat it with the marshmallow mixture.

Then pour the popcorn onto a baking sheet.  Drizzle the remaining marshmallow mixture on top.  Then top with the red M&Ms and the remaining mini marshmallows.

Allow the popcorn to cool at room temperature. Then break the popcorn into pieces and serve.