Mix butter and graham crackers in a small bowl until well combined.
Spoon graham cracker mixture evenly into the bottom of 12 muffin cups, save about 1/3 cup of the mixture for topping.
Chocolate Mixture
Place milk chocolate chips and whipping cream into a small bowl and microwave for about 25 second increments, stirring in between, until melted and smooth.
Spoon chocolate into the center of each cup, on top of the crust. Divide Marshmallows among cups.
Pudding Mix
Mix cold milk with pudding on medium speed for 2 minutes. Fold in half of the whipped topping.
Spoon filling into each cup evenly. Try to spoon it in between the marshmallows so that the whole cup is filled.
Use a knife to smooth the tops level with the top of the pan. Freeze for a couple of hours.
Allow the pan to warm just a bit before popping each dessert cup out.
For topping, spoon a little bit of the left over Cool Whip on each dessert.
Sprinkle the remaining crust and mini chocolate chips on top.
Serve cold right away– or put them in a sealed container and freeze until you are ready to serve.