Crush the Oreos: Finely crush 48 Oreo cookies until you have fine crumbs, then divide into three portions of about 16 cookies each.
Make the crust: In a bowl, combine the first portion of crushed Oreos with the melted butter and mix until the texture resembles wet sand.
Press into the pan: Press this mixture firmly into the bottom of a 9x13 inch baking dish, creating an even, compact base layer.
Beat the cream cheese: In a large mixing bowl, beat room temperature cream cheese with powdered sugar and vanilla extract until light and fluffy, about 2-3 minutes.
Fold in Cool Whip: Gently fold the thawed Cool Whip into the cream cheese mixture until no white streaks remain.
Fold in second portion of Oreos: Fold in the second portion of finely crushed Oreos until evenly distributed throughout the filling.
Spread over crust: Spread this creamy mixture evenly over your cookie crust layer, smoothing the top with a spatula.
Prepare the pudding: In a bowl, whisk together the instant chocolate pudding mix with 3 cups of cold half and half or whole milk for 2 minutes until thickened.
Spread evenly: Pour the chocolate pudding over the cream cheese layer and spread it out in an even layer across the entire dish.
Top with third portion of cookies: Sprinkle the third portion of finely crushed Oreos over the pudding layer for extra texture and flavor.
Add the final topping: Spread the remaining 8 ounces of thawed Cool Whip over the pudding and cookie layer, creating a smooth finish.
Garnish generously: Top with crushed Oreo cookies or chocolate shavings for a decorative and delicious finishing touch.
Chill thoroughly: Cover with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the layers to set.
Serve chilled: Cut into squares and serve directly from the refrigerator for the best texture and presentation.