Add the cold milk to a medium-sized (2-3 quarts) mixing bowl. Sprinkle both packages of the instant pudding mix over the milk. Use either a handheld whisk or a handheld electric mixer on low speed to blend the milk and pudding until thickened, about 2 ½ -3 minutes.

Use a silicone spatula to gently fold the thawed whipped topping into the pudding. (Folding the whipped topping into the pudding should help keep the filling from becoming too dense)

Line the bottom of a 9x13 baking dish (I used a glass baking dish) with a single layer of graham crackers.

Lay a single layer of sliced bananas on top of the layer of graham crackers.

Spoon ½ of the pudding mixture on top of the layer of bananas. Use a silicone spatula or an offset spatula to smooth the pudding over the bananas.

Repeat the layers of graham crackers, sliced bananas, and the remaining ½ of pudding.

Layer the final sleeve of graham crackers on top of the top layer of pudding.

Finally, remove the lid and metallic tamper-resistant covering from the frosting. It is very important that you remove all of the metal before microwaving the frosting. Heat the frosting at full power for 30-45 seconds until pourable. Carefully stir the frosting, then evenly pour it over the top layer of graham crackers, smoothing the frosting as you go. Cover the baking dish and chill in the refrigerator for 4 hours.

Just before you are ready to serve, carefully use a sharp kitchen knife to cut 3 slices x 5 slices. Garnish each slice with a reserved sliced banana. Store any leftovers covered in the refrigerator for up to 4 days. You can freeze the banana eclair cake for up to 3 months. I recommend that you do not garnish the cake before freezing. The bananas will be affected by the freezing and thawing process.