Add 2 cups of crushed Oreo cookies to a bowl with the melted butter and mix with a fork until combined.
Press the Oreo cookie mixture into the bottom of a spring-form pan and up the sides of the pan about 2/3 of the height of the pan. Set the crust aside to chill in the fridge while you make the cheesecake filling.
For the cheesecake:
Add the cream cheese to a large bowl and whip until smooth with the powdered sugar.
Fold in the whipped cream and the green food colouring.
Add the peppermint extract and the mini chocolate chips and fold them in just until combined.
Pour the cheesecake mixture into the chilled crust, pressing it evenly into the bottom and sides of the pan and smoothing out the top to prevent air bubbles.
Chill the cheesecake for 24 hours in the fridge before serving, or chill in the freezer for 2-3 hours and then overnight.
Serve with a dollop of whipped cream (fold in a few teaspoons of cocoa powder to make chocolate whipped cream) and some chocolate sauce.