In a medium saucepan, whisk together the sugar, flour, and salt. Slowly pour in the milk, stirring constantly until fully combined. Place the saucepan over medium heat, cooking and whisking regularly until the mixture begins to thicken and bubble. Once thickened, reduce the heat to low and continue to cook for another 2 minutes. Remove the pan from heat.

In a separate small bowl, beat the eggs. To temper them and prevent curdling, whisk a small amount of the hot pudding mixture into the eggs. Then slowly pour the egg mixture back into the saucepan with the rest of the pudding, stirring continuously. Return the pan to medium heat and bring the custard to a gentle boil, cooking for an additional 2 minutes until thick and glossy. Remove from the heat and stir in the vanilla extract. Allow the custard to cool for about 15 minutes, stirring occasionally.

In an ungreased 8-inch square baking dish, arrange about 25 vanilla wafers on the bottom in a single layer. Add half of the banana slices on top of the wafers. Pour half of the warm pudding mixture over the bananas, spreading evenly with a spatula.

Repeat the layers with the remaining vanilla wafers, bananas, and pudding, ending with the final layer of pudding on top.

Cover the dish tightly with plastic wrap, making sure the wrap touches the surface of the pudding to prevent a skin from forming. Place the dish in the refrigerator for at least 4 hours, preferably overnight, to allow the flavors to develop and the pudding to set.

Before serving, crush the remaining vanilla wafers and sprinkle them on top for extra crunch and a decorative finish. Serve cold and enjoy the creamy, nostalgic taste of this homemade dessert.