Preheat oven to 350 degrees. Line a standard muffin tin with cupcake liners or spray with non-stick cooking spray.
Place the cake mix in a large bowl and whisk in the pudding mix and ¾ cup of the crushed vanilla wafers.
1 box yellow cake mix, 1/4 cup French vanilla pudding mix, 1 cup crushed Nilla wafers
Add the water, oil, eggs, and mashed bananas. Mix on medium speed with an electric mixer until the ingredients are well incorporated.
3/4 cup water, 1/3 cup vegetable oil, 3 egg yolks, 2 large banana
Spoon batter into the muffin cups until each is about 2/3 full, then sprinkle some of the remaining crushed vanilla wafers on top.
1 cup crushed Nilla wafers
Bake for 18-20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Place on wire racks and allow to cool to room temperature before frosting.