Place butter in a 9-inch pie plate; microwave 30 to 45 seconds to melt.
Stir in wafer crumbs.
Press into bottom and up sides of pie plate.
Microwave 2 minutes, turning dish every 30 seconds.
In a large bowl, mix marshmallows and milk.
Microwave 3 to 4 minutes; stirring smooth.
Beat in creme de cacao and cognac.
Chill 30 minutes, stirring once or twice.
Fold in whipped cream and pour onto crust.
Cover; chill 4 hours.
Peel chocolate with vegetable peeler and let curls fall onto pie.