Set aside 4 cookies. Crumble the remaining Oreo cookies in a food processor or crush in a plastic ziploc bag with a rolling pin.

In a large mixing bowl, combine the crushed cookies and cooled melted butter.

Spread and press down the crust mixture into a 9x13 baking dish with your hands or the back of a spatula. Place in the refrigerator to chill while preparing the other layers.

In a large mixing bowl, beat the softened cream cheese, powdered sugar and lemon zest until smooth.

Spread the cream cheese mixture evenly across the top of the chilled cookie crust. Return the baking dish to the refrigerator while you prepare the next layer.

In a medium bowl, whisk together the dry lemon pudding packets with the cold milk until smooth.

Spread the pudding layer across the top of the cream cheese layer.
Next, spread the remaining whipped topping over the top of the pudding layer.

Crumble the remaining Oreo cookies and use to garnish the top of the cake.

Chill in the refrigerator for at least 1-2 hours, or overnight, before serving. Slice and serve.