Prepare the cake according to the instructions on the box and bake it until done.

Once baked, take the cake out of the oven and let it cool for 10 minutes.

Using the back of a spoon, create evenly spaced holes throughout the cake.

Warm the hot fudge in the microwave until it reaches a pourable consistency. Pour the hot fudge evenly over the cake, allowing it to seep into the holes.

Let the cake cool completely.

In a medium-sized bowl, mix the chocolate pudding mix with milk until well combined. Before the pudding fully sets, pour it over the cooled cake.

Refrigerate the bowl until the pudding sets completely, which should take around 10 minutes.

Mix in about 3/4 of the crushed Oreos, then spread the pudding mixture evenly over the cake.

Sprinkle the remaining crushed Oreos on top of the cake, and either serve immediately or refrigerate until ready to serve.