Place the Oreo cookies in a food processor and pulse until crushed. (You could also put the cookies in a ziplock bag and crush them with a rolling pin). Reserve 1/2 cup of the crushed Oreo crumbs for topping.
Pour remaining crumbs into a 9x13'' baking dish. Drizzle the melted butter over the Oreo crumbs and gently toss with a spoon. Press the mixture firmly into the pan to form a crust.
In a large bowl whisk together the chocolate pudding mixes and milk. Refrigerate.
In another bowl blend together the cream cheese and powdered sugar until smooth. Fold in one container of Cool Whip. Add one drop of green food coloring, if desired.
Gently spread this mixture evenly over the Oreo crust. Pour chocolate pudding over the cream cheese mixture and smooth into an even layer.
Dollop small spoonfuls of the remaining Cool Whip over the top of the pudding and gently smooth it into an even layer. Sprinkle reserved Oreo crumbs on top.
Refrigerate until ready to serve. (Sometimes I even put it in the freezer, then remove it about 20-30 minutes before I serve it.)