In a medium mixing bowl, whisk together flour, baking soda, baking powder, salt and sugar.

Add butter. Mix on low speed.

Pour buttermilk into dry mixture. Add mashed bananas. Continue to mix on low speed for 3 minutes until mixture is creamy.

Add eggs, mixing after each egg.

Pour into prepared baking dish.

Bake for 30-35 minutes or until tooth pick inserted comes out clean.

Poke holes all over top of cake with end of wooden spoon.

Let cake cool before covering cake with pudding.

Once cake has cooled, beat pudding mix and milk in a medium mixing bowl for 2 minutes.

Pour pudding over cake right after mixing covering the cake completely (the longer the pudding sets up, the harder it is to get down into the holes).

Add a layer of sliced bananas over pudding.

Next, add a layer of vanilla wafers.

Top with whip topping.

Gently cover with plastic wrap. Refrigerate over night.

Optional, when ready to serve, slice additional banana and place on each piece of cake with vanilla wafers.