
In a food processor or blender, blend Oreos (whole cookies) into fine crumbs. Add melted butter and mix until combined. Press the mixture into the bottom of a 9x13-inch dish and place in the freezer or fridge for 5 minutes.
In a medium-sized bowl, whip the cream cheese until fluffy with an electric mixer. Add in the sugar and milk. Mix until combined. Stir in 1 cup Cool Whip, then spread the mixture lightly over the crust. Place in the freezer or fridge for another 5 to 10 minutes.
In a separate bowl, whisk the pudding and cold milk together until thick. Once thickened, spread over the top of the cream cheese layer. Place back in the fridge for another 5 to 10 minutes to allow the pudding to set.
Once the pudding has set, spread the remaining Cool Whip on top and sprinkle with chocolate chips or crushed Oreos. Store in the refrigerator for 2 to 3 hours. Slice just before serving and enjoy while cold.