Spray an 8” x 8” baking tin with non-stick cooking spray. Set aside.
In a large bowl, stir 3 ½ cups of the mini marshmallows with the melted butter until the marshmallows are well coated.
Put the bowl of marshmallows in the microwave for one minute. Remove from microwave and stir well to make sure all marshmallows are melted.
Add Rice Krispies & ½ cup graham cracker crumbs to the marshmallow mixture. Stir well to evenly coat Rice Krispies.
Place Rice Krispies mixture into the baking tin and use your hands to push it down firmly in the baking tin. Wet your hands slightly with cold water to prevent the mixture from sticking to your hands.
In a small bowl, melt chocolate chips in microwave (about 1 minute).
Pour 75% of the melted chocolate over the Rice Krispies mixture and spread the chocolate to evenly coat the top.
Use the remaining ½ cup marshmallows to sprinkle over the top of the melted chocolate.
Sprinkle the remaining 1 tablespoon of crushed graham crackers over the top.
Drizzle the remaining melted chocolate over the top.
Place the S’mores Rice Krispies Squares in the freezer for about 5 minutes so the chocolate hardens.
Cut into squares and serve.