Start by pouring 1 ½ cups of the nonfat milk into a large mixing bowl. Add the instant vanilla pudding mix and whisk vigorously for about 2 minutes until the mixture thickens. Let it sit for 5 minutes to set properly, creating a smooth, creamy base.
While the pudding sets, place 24 Oreos in a large plastic bag and crush them into small pieces using a rolling pin or the bottom of a sturdy glass. You want a mix of crumbs and small chunks for texture. Set aside the remaining 12 Oreos whole for layering.
Take the container of whipped topping and gently fold half of it into the prepared pudding. Use a spatula to combine them until the mixture is light and fluffy, perfect for the creamy layers in the dessert.
In your 9x13 inch baking dish, begin by spreading half of the crushed Oreos evenly on the bottom. Next, spread half of the pudding-whipped topping mixture on top of the crushed Oreos. Then, layer 6 of the whole Oreos across the pudding layer, spacing them evenly. Repeat the process with the remaining crushed Oreos, pudding mixture, and whole Oreos.
Finish your Oreo Lasagna Dessert with the remaining whipped topping, spreading it evenly across the top. For an extra special touch, you can garnish with a few crushed Oreos or even some chocolate shavings.
Cover the dessert with plastic wrap or foil and refrigerate for at least 4 hours, or overnight if possible. This chilling time allows the layers to set and the flavors to meld beautifully. When ready, slice into squares and serve chilled.