Preheat your oven to 350°F (175°C). Grab a food processor and pulse the Nilla Wafers until you have fine crumbs. If you don’t have a food processor, you can place the wafers in a resealable bag and crush them gently with a rolling pin. Next, transfer the crumbs to a mixing bowl and stir in the melted butter and brown sugar until everything is well combined. Use the back of a measuring cup to press this mixture firmly into the bottom and up the sides of a 9-inch pie plate. Bake in your preheated oven for 10 minutes. Once done, let the crust cool completely before you add the custard filling.

In a medium bowl, whisk together the egg yolks and cornstarch until smooth and well blended. Set this mixture aside for later. In a large, heavy-bottomed saucepan, combine the sugar, salt, and whole milk. Whisk everything together and bring it to a simmer over medium heat, stirring continuously to prevent sticking.

Now, it’s time to slowly incorporate the egg mixture. Take a ladleful of the hot milk and gradually stir it into the egg yolk mixture, whisking constantly. This technique tempers the eggs, preventing them from scrambling. Once combined, pour the tempered egg mixture back into the saucepan. Continue to cook, stirring constantly, until the mixture thickens enough to coat the back of a spoon. Remove from heat and stir in the butter and vanilla extract until melted and incorporated.

For an added layer of smoothness, strain the custard through a fine-mesh sieve into a storage container. Cover the surface of the custard with plastic wrap to prevent a skin from forming, and let it cool for about 30 minutes.

Slice your bananas and sprinkle the lemon juice over them to help keep them fresh and bright. Once the crust is cooled, arrange the banana slices on the bottom. Then, pour the cooled custard over the bananas, spreading it evenly. To prevent a skin from forming on the custard, place a piece of plastic wrap directly over the pudding's surface. Refrigerate for at least 4-6 hours, allowing the flavors to meld and the pie to set.

When you’re ready to serve, whip the heavy cream and powdered sugar together in a mixing bowl until soft peaks form. Gently spread the whipped cream over the top of the chilled pie, bringing it to a smooth, silky finish.

Allow the pie to chill in the refrigerator for another hour after adding the whipped cream for the best texture. Slice, serve, and watch as everyone falls in love with each creamy bite.