Preheat your oven to 350°F (175°C). In a large mixing bowl, combine the devil’s food cake mix, sour cream, vegetable oil, eggs, vanilla extract, and warm water. Mix until smooth and well combined. Pour the batter into a greased 9x13-inch baking pan and bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
While the cake is baking, prepare the instant chocolate pudding. In a separate bowl, whisk together the two packages of pudding mix and the whole milk. Stir until the mixture thickens. Set aside.
Once the cake has finished baking, remove it from the oven and let it cool for about 15 minutes. Using a fork or a skewer, poke holes all over the top of the cake.
Pour the prepared pudding over the top of the cake, making sure it fills the holes. Gently spread it out with a spatula to cover the entire surface.
In a mixing bowl, fold the thawed whipped topping into the remaining pudding. Spread this mixture over the pudding layer on the cake. Crumble about 15 Oreo cookies and sprinkle them on top.
Cover the cake with plastic wrap and refrigerate for at least 4 hours, or overnight if possible.
