Place Oreo cookies in a food processor (or smash in a sealed bag) to make fine crumbs.
In a mixing bowl mix crumbs with melted butter until evenly moistened. Press crumbs in bottom and up sides of sprayed 9-inch pie plate. Let crust set up in freezer while you work on the filling.
Custard Filling
In a small bowl mix the egg yolks and cornstarch together with a fork. Set aside.
Combine milk, heavy cream, sugar, and salt in a medium saucepan, over medium heat. Whisk until sugar dissolves, then bring to a gentle simmer, whisking occasionally. Use medium low heat or just enough heat to simmer, not scorch.
To temper the egg yolks: When simmering, remove about ½ cup of the milk mixture and whisk into the egg yolk and cornstarch mixture in a slow and steady stream. Keep stirring to avoid cooking the eggs.
Slowly pour and whisk the egg yolk mixture into the simmering saucepan. The pudding will immediately begin to bubble and thicken. Simmer for 1 minute, whisking constantly.
Remove from heat and whisk in vanilla and butter. If chunky, strain through mesh sieve.
Place a piece of plastic wrap directly on top of the warm pudding to prevent a skin from forming on top. Allow to cool for 15 minutes.
Slice 2–3 Bananas and arrange slices on top of pie shell. Spoon custard on top and spread with spatula. Top with plastic wrap, directly on top of the custard. Refrigerate for at least 4 hours. You can shorten the time by placing in freezer for first hour.
Whipped Cream Topping
Pour chilled heavy cream, powdered sugar, and vanilla into a large mixing bowl. Beat on medium-high speed approx. 2 minutes, until thick and spreadable.
If desired, you can add sliced bananas on top of the chilled pie filling. Spread or pipe whipped cream onto the top of the pie.
Slice, serve and enjoy!
Notes
Use Cool Whip in place of homemade whipped cream if desired.