Preheat the oven to 375 degrees.

In a small bowl, stir the sugar, cornstarch and salt together.

In a medium saucepan, whisk the 4 egg yolks with the milk and pour in the sugar mixture. Continue to stir over medium heat for about 8-10 minutes until the pudding has thickened. Remove from the heat and stir in the butter and vanilla. Set aside to cool slightly.

Using a mini muffin pan (pictured is silicone, so not necessary to spray or line it, but if using metal, I would advise to either spray or use mini cupcake liners), place a wafer, flat side down in the bottom of each cup. Next, place a slice of banana on top of each wafer.

Using a spoon, carefully add the pudding on top to cover and go down the sides of each banana slice and cookie. Do not overfill as you will be adding a meringue topping.

In a medium sized bowl, place the 4 eggs white and using a hand mixer (stand mixer works equally as well), start beating the eggs whites while slowly adding the sugar until it is incorporated. Stiff peaks will form when they are done.

Place the egg whites in a piping bag and cover the top of each bite. Place the tray in the oven and bake for 7-10 minutes, until the tops are slightly browned. Keep a close eye as they can turn brown very quickly. Remove and either serve warm, or they can be chilled and served cold. Keep any leftovers in an airtight container for up to 2 days in the refrigerator.