Crush the graham crackers and combine them with melted butter and sugar. Press this mixture into a 9-inch pie pan, using a measuring cup to ensure it's level and pressed up the sides.

Bake the crust at 350°F until it turns golden around the edges, which should take about 10 minutes. Allow it to cool afterward.

In a saucepan, mix together the milk, heavy cream, sugar, and a pinch of kosher salt. Heat this mixture over low heat until the sugar has dissolved.

Separate the eggs, placing the whites in one bowl and the yolks in another. Whisk the cornstarch into the yolks.

Temper the yolks by gradually adding a small amount of the hot milk mixture while whisking. Then, pour the yolk mixture back into the saucepan and whisk continuously until the pudding thickens.

Remove the pudding from heat and stir in the cold butter and vanilla extract.

Spread a thin layer of the pudding over the cooled crust, then layer sliced bananas on top. Add more pudding and bananas, and refrigerate the assembled dessert.

Whip the egg whites until they reach medium peaks, gradually adding sugar and a pinch of salt. Continue whipping for 7-8 minutes until the mixture is glossy and smooth.

Spread the meringue over the chilled banana pudding. You can either torch it or bake it at 450°F for about 5 minutes until it is browned.

Serve the banana pudding warm, at room temperature, or chilled.