1. In a medium saucepan, melt chocolate over low heat. While it melts, whisk sugar, milk and egg yolks in a medium bowl. Once chocolate is melted, add sugar/egg mixture. Stir constantly until smooth and thickened, about 7-9 minutes. Remove from heat. Cool completely.
2. In bowl of a stand mixer, cream butter on medium speed until fluffy, then add half of confectioners sugar and beat for 2 more minutes.
3. Add cooled chocolate mixture to butter and beat well. Leave in mixing bowl.
4. In a separate mixing bowl, whip egg whites and salt to stiff peaks. Gradually add in remaining confectioners sugar.
5. Fold egg white meringue into chocolate mixture, then add vanilla. Place mixture in refrigerator to cool for one hour or more.

Assembly:

1. Line 8 dessert glasses in a row in assembly line fashion.  Spoon graham crumbs evenly into each glass.
2. Mix marshmallows into container of mousse; top the graham with the mousse.  Add a spoonful of syrup to the top of mousse, then pipe or spoon a dollop of whipped cream to top of glass.  Garnish with chocolate shavings, if desired.