Mix the chocolate crumbs and melted butter and press them firmly into a 9-inch pie plate; refrigerate for 20 minutes.
Melt the marshmallows with the milk in a saucepan over low heat for 4 to 5 minutes, stirring until smooth.
Remove from the heat, stir in both liqueurs and the salt, and cool for 25 minutes until no longer warm.
Beat the heavy cream to medium peaks and fold it into the marshmallow mixture in 3 additions.
Spread the filling in the crust and refrigerate for at least 6 hours before slicing.