*Place cool whip in the refrigerator a few hours before you start to make the recipe so it has time to thaw, it'll be easier to mix with the pudding that way.*
Line a 8x8 inch baking pan with parchment paper or plastic wrap. Leave enough to go over the sides of the pan so you can easily transfer the cake when ready to serve. Set aside.
Prepare the pudding in a large mixing bowl according to package instructions. Set the pudding in the refrigerator for 30 minutes to firm up slightly. Remove the pudding from the refrigerator and add the cool whip into the pudding, using a handheld mixer to combine the two together until combined.
Line the bottom of the baking pan the a single layer of gramham crackers. You may need to break a few in half or in smaller pieces to cover the pan completely, including the corners. Layer half of the pudding/cool whip mixture over the layer of graham crackers, smoothing it out to from a thick, even layer. Lay another single layer of graham crackers over the pudding mixture. Spoon the last of the pudding mixture over the middle layer of graham crackers. Lay a final layer of graham crackers over the top pudding layer. So you should have 3 graham cracker layers, 2 pudding layers. Place the baking pan in the freezer to set while you make the chocolate icing.
Make the icing: measure out the chocolate chips and place them in a bowl, set aside. Place a saucepan over low medium heat and add to it the heavy cream, butter, corn syrup and espresso powder. Whisk the ingredients together, allowing them to come to a soft boil, whisking the mixture occasionally, be careful not to let it burn. Once the mixture starts to bubble, remove the saucepan from the heat and pour it directly over the chocolate chips. Let the chocolate chips sit in the hot cream mixture undisturbed for a few minutes. After a few minutes, mix everything together until chocolate chips are completely melted and smooth. Remove the cake from the freezer and pour the chocolate icing directly over the top of the cake, smoothing it with a spoon. Cover the top of the pan with plastic wrap and place the pan in the refrigerator to set for at least 4 to 6 hours or up to overnight. When ready to serve simply lift the cake up by the sides of the parchment paper, cut into slice and serve.