Step 1: In a large mixing bowl, whisk together the instant vanilla pudding and milk until well combined. Let the mixture sit for about 5 minutes until it thickens.
Step 2: Add the cup of sour cream, sweetened condensed milk, and vanilla extract to the pudding mixture. Use your whisk to mix everything until smooth and creamy.
Step 3: Gently fold in the thawed Cool Whip using a spatula. This will give your pudding a light and airy texture, making it even more irresistible.
Step 4: In a 9x13 inch baking dish, start by laying down a layer of vanilla wafers. Follow this with a layer of sliced bananas, then a layer of the pudding mixture. Repeat the layers until all ingredients are used, finishing with the pudding mixture on top.
Step 5: Take the reserved vanilla wafers and crush them into small pieces. Sprinkle the crushed wafers over the top layer of the pudding for a crunchy finish.
Step 6: Cover the dish with plastic wrap and let it chill in the refrigerator for at least 4 hours, preferably overnight. This allows the flavors to meld beautifully. Once chilled, serve and enjoy this delightful dessert!