Preheat oven to 350 degrees.

Grease a 9×13 baking dish.

In the bowl of a stand mixer add the cake mix, eggs, water and butter.

Beat on medium speed for 2 minutes.

Meanwhile, mash bananas in a separate bowl.

Fold bananas into cake batter and stir until combined.

Pour into prepared 13×9 baking dish.

Bake for 30 minutes or until a skewer inserted into the center of the cake comes out clean.

Allow to cool for 10 minutes.

Use the handle of a wooden spook to poke holes all over the top of the cake. Be careful not to go all the way to the bottom.

In a bowl, combine the instant pudding and milk; whisk until combined.

Allow pudding to set for about 2 minutes.

Pour slightly thickened pudding over the top of the cake. Use a spatula to spread it evenly, allowing it to fill the holes.

Refrigerate for at least 30 minutes.

Meanwhile, add whipping cream to the bowl of a stand mixer; Whip cream till soft peaks form.

Fold in powdered sugar and vanilla and beat until thoroughly mixed.

Spread the whipped cream on top of the chilled cake.

Top with crushed vanilla cookies and garnish with banana slices. Add these to the cake when you're about to serve. This way the cookies don’t get soggy and the bananas stay fresh.