Preheat oven to 350 degrees. Spray a 13x9 pan with nonstick cooking spray and set aside.
Prepare cake according to directions.
Pour cake mix into a 13x9 pan and bake according to package directions.
1 package chocolate cake mix, 1 cup water , 1/3 cup vegetable oil, 2 eggs
In a medium saucepan, combine the sugar, cornstarch and salt.
3/4 cup sugar, 3 T cornstarch, 1/4 tsp salt
Add in the milk and cream and stir to combine.
2 cups milk, 1/2 cup heavy cream
Heat the milk to just under a boil.
When small bubbles start appearing on the sides of the pan, it’s time to temper the eggs.
Take 1/2 cup of the milk and slowly whisk it into the egg yolks. The eggs are now tempered and ready to add the pudding.
2 egg yolks
Add the eggs to the pudding and cook for 3 minutes then remove from the heat.
Stir in the vanilla and the butter. Set the pudding aside to cool a little.
1 tsp vanilla extract , 3 T butter
With the handle of a wooden spoon, poke a hole in the cake.
Pour the pudding over the top of the cake, guiding the pudding into the holes.
Place the cake in the refrigerator for 30 minutes.
Take 5 Oreos and crush the chocolate cookies into crumbs and stir them into the 8 ozs of cool whip.
Top the cake with the cool whip and return it to the refrigerator for another 30 minutes.
1 package whipped cream
Just before serving, Crush the remaining 15 Oreo cookies and sprinkle them on top of the cake.
Garnish with a little chocolate syrup and serve immediately.