In a medium saucepan, whisk together 1 cup of sugar, 1/3 cup of flour, and a pinch of salt until well blended.

Gradually pour in 4 cups of milk while whisking continuously over medium heat. Keep stirring for about 10 minutes until the mixture thickens.

Once thickened, reduce the heat to low and let the pudding gently bubble for an additional 2 minutes, stirring constantly.

In a small bowl, whisk together 3 beaten eggs. Gradually stir in about one cup of the hot pudding mixture to temper the eggs.

Pour the tempered egg mixture back into the saucepan with the remaining pudding. Cook on low heat, stirring constantly until it thickens.

Remove the saucepan from heat and stir in 1 tablespoon of pure vanilla extract. Let the pudding cool for approximately 15 minutes.

In an ungreased 8-inch square pan, begin layering by placing about 25 vanilla wafers at the bottom.

Add half of the sliced bananas before pouring in half of the warm pudding mixture. Repeat these layers once more.

Cover the pan closely with plastic wrap and refrigerate for at least 4 hours, preferably overnight.

Before serving, sprinkle crushed vanilla wafers on top for added crunch.