Prep your pan: Lightly grease a 9x13-inch baking dish or line it with parchment for easy slicing and lift-out.
Make the crust: Crush the chocolate sandwich cookies into fine crumbs using a food processor or a zip-top bag and rolling pin. Stir in the melted butter until the mixture looks like wet sand.
Press and chill: Firmly press the crumb mixture into the bottom of the dish in an even layer. Use the bottom of a measuring cup to compact it.
Chill in the fridge for 10–15 minutes while you prep the next layer.
Whip the cheesecake layer: In a mixing bowl, beat the softened cream cheese, powdered sugar, and vanilla until smooth and fluffy. Gently fold in 1 cup of the whipped topping until just combined.
Spread the cheesecake layer: Dollop over the chilled crust and spread evenly to the edges. Return to the fridge to keep it cool.
Mix the pudding: In a large bowl, whisk the instant chocolate pudding mixes with cold milk for about 2 minutes, until thickened.
Let it sit for another 2–3 minutes to fully set.
Add the pudding layer: Spread the pudding over the cheesecake layer in an even, smooth blanket. Try not to lift the pudding as you spread to avoid mixing layers.
Top with whipped topping: Spread the remaining whipped topping over the pudding. Keep the strokes light to maintain clean layers.
Finish with chocolate: Sprinkle chocolate chips or shavings on top.
Add a light drizzle of chocolate or caramel sauce if you like.
Chill to set: Cover the pan and refrigerate for at least 4 hours, ideally overnight. This helps the layers firm up for neat slices.
Slice and serve: Cut into squares with a sharp knife. Wipe the knife between cuts for clean edges.