In a mixing bowl, combine the chocolate cookie crumbs and melted butter. Stir until the crumbs are evenly coated. Press the mixture into the bottom and up the sides of a 9-inch pie dish to form the crust. Place it in the refrigerator to chill for about 30 minutes.
In a saucepan, combine the marshmallows and water. Heat the mixture over low heat, stirring constantly, until the marshmallows are completely melted and smooth.
In a clean mixing bowl, whip the egg whites using an electric mixer on medium-high speed until soft peaks form.
Add the granulated sugar to the whipped egg whites and continue to beat on medium-high speed. Beat until stiff peaks form and the sugar is fully incorporated.
In a large bowl, combine the melted marshmallow mixture, green crème de menthe liqueur, whipped cream, white crème de cacao liqueur, whipped heavy cream and whipped egg whites until fully incorporated.Be careful not to overmix and deflate the whipped cream, just fold all the ingredients carefully.
Remove the pie crust from the refrigerator. Pour the grasshopper filling into the crust, spreading it evenly.
Return the pie to the refrigerator and let it chill for at least 4 hours, or until set.
If desired, garnish with chocolate shavings on top and serve with chocolate sauce if desire!
Slice and serve chilled.