Preheat your oven to 350°F (175°C). In a large mixing bowl, combine the chocolate cake mix with the required ingredients as per the package instructions. Grease a 9x13 inch baking pan and pour the cake batter into it. Bake in the preheated oven for about 30 minutes, or until a toothpick inserted in the center comes out clean, and the cake is slightly springy to the touch.

Once your chocolate cake is baked, remove it from the oven and let it cool for about 10 minutes. Using the handle of a wooden spoon, poke holes into the warm cake at 1-inch intervals across the surface.

In a separate mixing bowl, whisk together the 4 cups of cold milk with the two packets of instant Oreo pudding. Mix vigorously until fully combined and smooth in texture. Let it sit for about 2 minutes to thicken.

Pour the thickened Oreo pudding mixture evenly over the warm cake, ensuring it seeps into the holes you created earlier. Allow the cake to cool completely at room temperature before transferring it to the refrigerator.

Chill the cake in the refrigerator for at least 1 hour. Once chilled, spread the Cool Whip evenly over the top of the cake to create a light, fluffy finish. Sprinkle the crushed Oreo cookies on top just before serving.