Grease a 9x13 inch dish. Prepare chocolate cake according to box directions adding in around ½ cup of roughly chopped oreos.
Pour cake batter into the prepared pan. Bake for 30-32 minutes or until a tooth pick inserted in the center comes out clean.
While the cake is cooling whisk milk and pudding together until smooth.
Use a wooden spoon to poke holes in the top of the cake. Evenly pour pudding over the top of the cake.
Sprinkle with ~half of the chopped oreos. Cool cake completely.
Frost with cool whip. Sprinkle with remaining oreos. Store in the refrigerator.
Notes
Ingredient Notes and Shopping Tips
Cake Mix: I used Betty Crocker's Chocolate Fudge flavor. Also, be sure to grab the ingredients called for on the box.
Oreo Pudding: I found the Oreo pudding at Walmart
If you can't find it, feel free to use vanilla pudding with some finely chopped Oreos instead.
Be sure whatever kind of pudding you use is instant, NOT cook and serve.
Milk: Pudding sets best when used with whole milk.
Cool Whip: Thaw Cool Whip overnight in the fridge. Avoid microwaving it, as this can cause it to separate.
Tips
Perfect Poking: Poke holes using the handle of a wooden spoon while the cake is still warm.
Poke around 1-2 inches apart to ensure you get some pudding in every bite.
Gently tap your pan on the counter to help the pudding move downwards.
How To Tell When It's Done: The cake is done when a toothpick inserted in the center comes out clean or with a few moist crumbs. If you see raw, batter, keep baking for a few minutes at a time.
Garnish Last: Add Oreos just before serving to ensure they don't get soggy.
Be sure not to poke the whole way through the cake or your filling will pool at the bottom and make the poke cake soggy.