Preheat the oven to 350°F. Line two standard muffin tins with paper liners. If you do not have a third muffin tin, repeat the baking process for any remaining cupcake batter.

Add the vanilla wafer crumbs and granulated sugar to a medium-size (2-3 quarts) mixing bowl. Stir to combine.

Add the melted and cooled butter, stirring to completely coat the vanilla wafer crumbs.

Use a 1 ½ tablespoon cookie scoop to scoop the buttered crumbs into the individual cupcake liners. Tamp down the crumbs.

Add the dry cake mix, milk, vegetable oil, eggs, egg white and the mashed bananas to a medium size mixing bowl. Use a handheld mixer on medium speed to mix together the ingredients until well combined.

Spoon the cake batter on top of the buttered crumbs, filling the liners about ⅔ full.

Bake for 20-25 minutes, or until a toothpick inserted comes away clean. (A few crumbs attached to the toothpick are fine. Also remember that all ovens cook differently, so begin checking the cupcakes at 12-15 minutes.) Remove the pan from the oven, and allow the cupcakes to rest for 2-3 minutes before transferring to a cooling rack. Repeat the process with the remaining cupcake batter.

Add the cold milk and cold heavy cream to a medium size bowl. Using either a handheld whisk or a handheld mixer on low speed, mix in the instant pudding mix. Continue to mix until the pudding thickens. (If you're using an electric mixer, this will take one to two minutes. If you're using a handheld whisk, it may take two to three minutes.)

While the cupcakes are cooling, if you have a stand mixer, place the mixer bowl and the wire whisk attachment, or a medium size mixing bowl and the handheld mixer beaters in the freezer. (30 minutes is the recommended time, this will help when making the homemade whipped topping.)

Use a teaspoon to scoop out the center of the cupcake, about the size of a quarter and down about ½ inch.

Add the pudding to either a disposable piping bag with the end snipped off, or a gallon-sized Ziploc bag with the corner snipped off.

Using even pressure, squeeze the pudding into the open cavity of the cupcake, and fill just to the top of the opening. Repeat for the remaining cupcakes. Place the filled cupcakes in the refrigerator while you make the homemade whipped topping.

Once the cupcakes have chilled for 30 minutes, add the cold heavy cream, powdered sugar and vanilla to the mixer bowl. Mix on medium high speed until the whipped cream begins to reach the soft peak stage, about two to three minutes. (The whipped cream will just begin to hold a loose shape, but not hold the peak.) Increase the speed to high and continue to mix until the whipped cream reaches the stiff peak stage, where it holds its shape. This will take an additional two to three minutes.

Add the homemade whipped topping to a disposable piping bag fitted with star shaped decorators tip, or a gallon-sized Ziploc bag with the end snipped off. Use steady, even pressure while piping the whipped topping from the center circling to the outer edge of the cupcake. Repeat for the remaining cupcakes.

Sprinkle a small amount of the crushed vanilla wafers on top of the whipped topping. Next slide one slice of banana into the whipped topping. Keep refrigerated until ready to serve. Store any leftovers in an airtight container for up to three days.