In a medium saucepan, combine the milk, sugar, flour, egg yolks, and salt. Whisk until smooth.

Place the saucepan over medium heat and cook the mixture, stirring constantly, until it thickens and comes to a boil. Remove from heat and stir in the vanilla extract.

In a separate bowl, beat the egg whites until stiff peaks form. Gently fold the beaten egg whites into the pudding mixture.

Slice the bananas and layer them along with the vanilla wafers in a serving dish or individual dessert cups.

Pour the pudding mixture over the banana and wafer layers, ensuring that all the layers are covered.

Repeat the layers until all the ingredients are used, ending with a layer of pudding on top.

Cover the dish or cups with plastic wrap and refrigerate for at least 4 hours, or until the pudding sets and the flavors meld together.

Before serving, garnish with additional sliced bananas and crushed vanilla wafers, if desired.