Split all the cookies open using a butter knife. Don’t worry if the icing comes off unevenly. Some cookies will have some icing, all the icing or none. It doesn’t matter.
Beat the milk and pudding mix with an electric mixer until thickened.
Fold in the whipped topping with a rubber spatula.
Place a layer of cookies, icing side up on the bottom of a dish. I found that 9×13 was a bit too big, but it can work. I ended up using one that is just smaller, about 8×1, You might also be able to use a 9×9 pan, but make sure it is deep.
Put a layer of cookies on the bottom.
Add half the pudding mixture.
Place another layer of cookies icing side up over the pudding.
Add the rest of the pudding.
Place the final layer of cookies, icing side down. Don’t worry if there are gaps between the cookies.