Prepare an 11x7 or 13x9 baking dish by spraying with a light coat of non-stick spray. Set aside.

In a large 6-qt stock pot, melt the butter over medium/low heat.

Add in the mini marshmallows and heat for an additional 5-10 minutes or until the marshmallows are melted and the mixture is smooth. Stir frequently to avoid scorching.

Immediately remove from the heat and stir in the cereal and graham cracker pieces. Stir well - scraping the bottom and sides often to thoroughly coat.

Working quickly, sprinkle with the mini chocolate chips and fold a few times to incorporate the chocolate chips, trying not to melt all the chips completely.

Pour into the prepared pan and use the spatula or hands sprayed with non-stick spray to help press the mixture into the pan.

Allow to set at room temperature for at least an hour to cool and set.

Slice and serve.