In a medium saucepan, whisk together 2/3 cup sugar, the cornstarch, instant espresso powder, and salt until combined. Slowly whisk in the whole milk, heavy cream, and vanilla extract until combined. Heat the mixture over low-medium heat, whisking often.

While the milk mixture heats, in a small bowl whisk together the egg yolks and remaining 2 tbs. of sugar until they become pale. Once the milk mixture is steaming hot, ladle in about 1 cup of the milk mixture into the egg yolk mixture very slowly, whisking constantly. This is to temper the egg yolks. Then, pour the egg mixture back into the pot, and whisk everything together. Whisk constantly over low-medium heat until the mixture becomes very thick, about 5-8 minutes.

Once the mixture thickens, remove it from the heat and continue to whisk for about 30 seconds-1 minute. If you see any lumps, push the custard through a fine mesh sieve at this point. Pour into a heat safe bowl, and cover with plastic wrap that is pressed directly on top of the custard. Chill the mixture for 1-2 hours, or until it is completely chilled through.

While the custard chills, make the crust. Preheat your oven to 350 degrees, and pull out a pie plate. Use a food processor to grind the oreos and sugar into fine crumbs. Stir in the melted butter until it is well distributed throughout the crumbs, and the mixture looks like wet sand. It should hold together when pressed. Pour the mixture into a 8 or 9 inch pie pan, and press into the pan gently all the way around and up the sides using a flat bottom of a glass or measuring cup. Bake the crust for 5-8 minutes, or until it looks dry and feels firm to the touch. Let the crust cool completely before continuing.

In a large bowl, or the bowl of a stand mixer, use a whisk attachment to whip the heavy cream until soft peaks form. Then, add in the instant vanilla pudding mix (optionally), and beat the cream until stiff peaks form.

Slowly fold the whipped cream into the chilled coffee custard, starting with about 1/4 cup of whipped cream that you can stir in vigorously to lighten the base of the custard. Then, fold in about 3/4 of the total whipped cream mixture to the custard, folding slowly and gently until fully combined. Spread the filling in your prepared pie crust evenly. Top the pie with the remaining whipped cream, and optionally add sprinkles or chocolate shavings.

Chill the pie for at least 3-4 hours before serving, or overnight. Enjoy!