1 (15-oz) box vanilla wafers (reserve a few to crush on the top)
1 (5.1-oz) box instant vanilla pudding
2 cups milk
½ cup sour cream
1 (14-oz) can sweetened condensed milk
2 tsp vanilla extract
1 (12-oz) container Cool Whip, thawed
6 bananas, sliced
Lightly spray a 9×13-inch baking dish with cooking spray.
Whisk together pudding mix and milk. Add sour cream, condensed milk, vanilla, and Cool Whip. Gently whisk until combined.
Layer in the baking dish: ½ of the vanilla wafers, ½ of the bananas, and ½ of the pudding mixture. Repeat the layers.
Crush the reserved vanilla wafers and sprinkle on top.
Cover and refrigerate at least 4 hours before serving.