Preheat the oven to 350°F (175°C).

In a food processor, crush the Oreos until fine.

Add the melted butter and pulse until well combined.

Press the mixture into a 10 inch pie pan or an 8x8 / 9x9 square or rectangular dish.

Bake for 8 minutes. Remove from oven and let cool completely.

In a medium bowl, beat the room-temperature cream cheese with the powdered sugar until smooth and creamy.

In a separate bowl, lightly whip the heavy cream until it holds soft peaks.

Gently fold the whipped cream into the cream cheese mixture until combined.

Spread the cream cheese filling evenly over the cooled crust. Refrigerate while preparing the pudding.

In a saucepan, whisk together the sugar, cornstarch, cocoa powder, and salt until evenly blended.

Gradually whisk in the milk.

Heat the mixture over medium heat, stirring constantly, until it begins to thicken.

In a small bowl, lightly beat the egg yolks. Temper the eggs by slowly whisking in a small amount of the hot chocolate mixture, then return the eggs to the saucepan.

Continue cooking over medium heat until the pudding thickens fully.

Remove from heat and whisk in the butter and vanilla extract until smooth.

Pour the chocolate pudding over the cream cheese layer.

Smooth the top with a spatula, and optionally place a piece of wax paper directly on top to prevent a skin from forming.

Chill the pie in the refrigerator for several hours (or overnight) until fully set.

Serve with whipped cream, if desired.