Prepare the Filling: In a large mixing bowl, beat the softened cream cheese and sweetened condensed milk together until smooth and fluffy, about 3 minutes.
Add the mint extract and a few drops of green food coloring (if using), mixing until evenly incorporated.
Gently fold in 12 ounces of Cool Whip along with the crushed Mint Oreo cookies. Mix until well combined.
Assemble the Pies: Divide the filling evenly between the two Oreo pie crusts, smoothing the tops with a spatula.
Make the Chocolate Ganache: In a microwave-safe bowl, combine the semi-sweet chocolate chips and heavy whipping cream. Microwave in 30-second intervals, stirring each time, until melted and smooth. Let cool for about 5 minutes.
Top the Pies: Pour the cooled ganache over each pie, spreading it evenly.
Chill: Refrigerate for at least 3 hours, or overnight, to allow the filling to set.
Serve: Slice and enjoy chilled! Garnish with extra Cool Whip, crushed Mint Oreos, or Andes mints if desired.