Line a 9 x 9-inch baking pan with parchment paper or foil and spray with nonstick cooking spray.

In large pan, melt butter over low heat. Set aside 1 cup marshmallows. Add the rest of the marshmallows to the pan and stir until completely melted.

Gradually add in the popcorn; stirring until well coated. Fold in the reserved 1 cup of marshmallows and mix until they are evenly incorporated.

Using a buttered spatula or clean hands to firmly press the mixture into the prepared pan. Cool completely. Cut into bars.

Melt chocolate candy melts according to package directions. Use a spoon to coat the top of the Movie Theater Popcorn with the melted chocolate. Immediately top with candies of your choice along with additional marshmallows and popcorn.