Place Graham crackers in a small plastic bag seal and crush with a rolling pin until medium fine. Place in a small bowl and add melted butter and mix until well blended. Spread on the bottom and sides of a tart or pie pan but do not press down firmly leave loose.
In a double boiler place the Milk, Hersey Bars and Marshmallows. Cook until all the ingredients are melted, set aside to cool. Place a paper towel over the pan to help avoid a skin on the mixture.
Whip the cream. Fold the cream into the cooled chocolate mixture, do not over mix but make sure all is blended well and that there are no large lumps of whipping cream.
Spoon the chocolate mixture on to the prepared graham crackers and smooth the top. I spoon a little more of the mixture toward the center to give it a little height int he center of the pie. Cover with plastic wrap and freeze until ready to serve. Remove from freezer about 10 minutes before serving.