All ingredients ready? Let's begin!
Set out the cream cheese so it can reach room temperature.
In a medium pot, add 3 cups of milk. Heat over medium-high. When the milk begins to simmer, add ¼ cup of sugar, the cocoa powder, and the cornstarch. Use a whisk to mix together.
Bring the milk to a boil while stirring constantly.
Cook and stir until the mixture thickens, around 2-5 minutes.
Transfer the pudding to a bowl and cover it with plastic wrap, pushing it down to rest on top of the surface of the pudding (to prevent a skin from forming).
Put the pudding in the fridge for several hours until chilled.
In a medium bowl or the bowl of a stand mixer, add the heavy whipping cream, powdered sugar, and vanilla.
Whisk together with an electric hand mixer or stand mixer for several minutes until stiff peaks form. Keep whisking it even after the stiff peaks; you want it extra thick. This can also be done by hand but it will take much longer.
Cover and place in fridge.
Crush the oreos. This can be done in several different ways. The easiest method is to pulse in a food processor until the cookies turn into fine crumbs. Another method is to put all the oreos into a ziplock bag and pressing the air out before sealing it. Use a meat mallet or rolling pin to smash the oreos into crumbs.
In a microwave safe bowl, add the butter. Pop it in the microwave for 30 seconds or until melted.
Set aside a handful of oreo crumbs and add the rest of the oreo crumbs to the butter and mix well. You can use a spatula, fork, or your hands.
Dump the buttered oreo crumbs onto the bottom of a baking dish. I usually use a 9x13 inch dish, but you can use a smaller one if you want thicker layers. Use your fingers to press the crumbs against the dish to form a crust. Put in the fridge.
In the bowl of a stand mixer affixed with the paddle attachment, add the softened cream cheese. Or add to a regular bowl and use an electric mixer or a spatula if you do not have a stand mixer.
Beat the cream cheese for 3 minutes or until pale and fluffy. Use a spatula to scrape down the sides of the bowl as needed.
Add ¼ cup of sugar and 2 tbsp of milk. Continue to mix for a couple of minutes.
Remove from the stand mixer. Add the previously made whipped cream and use a spatula to gently fold it together. Do not use an electric mixer for this as you want it to remain fluffy.
Get the crust out of the fridge and spread half of the whipped cream cheese mixture across in an even layer.
Return to the fridge to let sit for 10 minutes.
Take out of fridge and spread the set chocolate pudding across in an even layer.
Return to fridge and let sit again for another 10 minutes.
Take out of fridge and top with the remaining whipped cream cheese mixture. Spread in an even layer.
Sprinkle the rest of the oreo crumbs across the top and refrigerate for several hours to allow it to set.
When the oreo lasagna has set, slice and serve. Yum!