In a food processor, add Oreo® Chocolate Sandwich Cookies (300 gram) and Dark Chocolate (100 gram). Process until everything is combined.
Add Butter (70 gram) and process again until combined.
Transfer the cookie mixture into a 20-centimeter springform tin, greased and lined with non-stick baking paper. Using a flat-bottomed glass, press the mixture down until it is flat on bottom and pushed slightly up the sides. Put into fridge to chill for 30 minutes.
In a medium saucepan, add Marshmallow (150 gram), White Chocolate (200 gram) and Milk (1 cup). Over a low to medium heat, allow to melt together until smooth. Set aside to cool.
In a mixing bowl, beat Whipping Cream (600 milliliter) until mixture forms soft peaks.
In a large mixing bowl, add marshmallow mixture, Peppermint Essence (1 teaspoon), Green Food Coloring (to taste) and a quarter of the whipped cream mixture. Mix together and then stir in the remaining cream.
Transfer the liquid mixture onto the chilled cookie base.
Cover the pie with plastic wrap and chill in fridge for 3-4 hours, or until set.
Transfer pie to serving plate and top with Peppermint Chocolate Bar (1). Serve and enjoy!