Mix cream cheese and sugar until sugar is fully incorporated and not grainy. You can use a hand mixer, stand mixer, or do it by hand.
Next, fold cool whip into cream cheese/sugar mixture. Make sure that it is all the same consistency with no large lumps of cream cheese mixture.
Break up cookies into small pieces.(Do not pulverize the cookies into a powder. You also don't want huge chunks. You want to be able to have small chunks in the icing.) I find that crunching the cookies up by hand works best and you can control how small you break up the pieces.
Add the cookies to the Icing. Mix together until cookies are evenly distributed and no longer.
Ice your cake, slice and enjoy. and if you have extra Icing it's great to eat by itself or on top of oreo cookies.