Whisk together marshmallow creme and creme de menthe and stir until well blended. Mix in candy on low speed (save a piece if you like to use as garnish on top).
Whip cream (no extra ingredients needed for heavy cream) and fold into marshmallow mixture.
Pour into prepared crust (don't throw out that plastic covering the crust--use as an inverted lid for pie in freezer). Garnish with candies or sprigs of mint.
Freeze 2 hours or until firm.
Remove from freezer about 5 minutes before serving. If leaving out on table for awhile put a frozen ice pack under the pie to keep it cold as the whipping cream will wilt. It's so good it won't last long! This can be refrozen or you can slice how much you need and keep in freezer. Easy to do ahead of time for a great 'homemade' delicious frozen pie!