**Prepare the Crust**
Combine the crushed cookies and melted butter in a mixing bowl and stir until evenly combined. Press the mixture firmly into the bottom of a 9x13-inch baking dish. Chill in the refrigerator while preparing the layers.
**Cream Cheese Layer**
Beat the cream cheese, powdered sugar, and vanilla extract until smooth. Fold in 1 cup of the whipped topping. Spread this mixture evenly over the chilled crust.
**Pudding Layers**
Prepare the chocolate pudding and vanilla pudding separately, using 1.5 cups of milk for each. Whisk until thickened.
**Layer the Puddings**
Spread the chocolate pudding over the cream cheese layer, followed by the vanilla pudding.
**Whipped Topping**
Spread the remaining whipped topping over the pudding layers evenly.
**Chill and Garnish**
Cover with plastic wrap and refrigerate for at least 4 hours, or overnight for best results. Before serving, sprinkle with chocolate chips, sprinkles, or shaved chocolate.