Instructions

1. 1
   In a 13-x 9-inch glass dish, place one layer of graham crackers, breaking up the crackers as needed to fill the space.
2. 2
   In a large mixing bowl, whisk together the instant pudding mix and cold milk. Fold in the whipped topping.
3. 3
   Spread half of the pudding mixture over the graham crackers. Top with another layer of graham crackers. Spread the remaining pudding mixture over the graham crackers. Top with a final layer of graham crackers. Transfer the dish to the fridge to chill for 30 minutes.
4. 4
   While the cake layers are chilling, make the ganache topping: Finely chop the chocolate, and transfer it to a heat-safe bowl. In a small saucepan, heat the heavy cream on medium-low for 5 minutes until just boiling. Do not allow the cream to heat to a rolling boil. Slowly pour the hot heavy cream over the chopped chocolate. Allow the mixture to sit for two minutes before whisking until smooth.
5. 5
   Remove the chilled eclair cake from the fridge. Pour the prepared ganache over top. Smooth the ganache with a spatula.
6. 6
   Cover the eclair cake with the baking dish lid or plastic wrap and put it back in the fridge. Allow the cake to chill for at least 8 hours before serving.