Make both the Chocolate pudding as directed on the box.
Take the heavy cream, vanilla extract, and powdered sugar and mix on high speed until it becomes the consistency of cool whip.
To make this cake, first place a layer of graham crackers on the top of the Chocolate pudding of a 13- x 9-inch baking dish. Because of the shape of the dish, a few graham crackers will need to be broken up to evenly cover the base of the dish.
Add another layer of graham crackers, the whipped cream, and then a layer of graham crackers.
Then, add a layer of chocolate pudding and a layer of graham crackers.
Add a final layer of whipped cream. You can decorate the top with sliced strawberries
Once the layering has been completed, put the dish in the fridge to chill for 12 hours. This no-bake cake is best served chilled. Chilling the cake for at least 12 hours gives the pudding filling plenty of time to firm up while softening the graham crackers at the same time.
Notes
You can also replace the Jello-o chocolate instant pudding by vanilla pudding.