Peel the bananas and slice them into thin rounds. Place the slices in a bowl. Try to use ripe but firm bananas. Very soft bananas may become mushy.

In a saucepan, whisk together sugar, cornstarch and milk. Cook over medium heat. Stir constantly until the mixture becomes warm and slightly thick.

Place the egg yolks in a small bowl. Slowly add a few spoonfuls of warm milk mixture. Whisk quickly. This step prevents the eggs from scrambling.

Pour the egg mixture back into the saucepan. Continue cooking over medium heat. Stir constantly until the pudding becomes thick, smooth and creamy.

Remove the pan from heat. Stir in butter and vanilla extract. Mix until the butter melts completely. Let the pudding cool for a few minutes.

In a mixing bowl, add heavy cream and powdered sugar. Use a whisk or mixer to whip until soft peaks form. The cream should look light and fluffy.

Place a layer of vanilla wafer cookies at the bottom of a serving dish. Spread them evenly so the base is fully covered.

Place sliced bananas over the cookies. Spread them evenly so each bite will have banana flavor.

Pour a layer of warm pudding over the bananas and cookies. Use a spatula to spread it smoothly across the dish.

Add another layer of cookies, bananas and pudding. Repeat until the dish is full. Finish with pudding on the top layer.

Spread the whipped cream over the pudding. Smooth it gently with a spatula. This layer makes the dessert light and creamy.

Place the pudding in the refrigerator for at least one hour. Chilling helps the flavors mix together and softens the cookies nicely.