For the Crust

1. Preheat your oven to 350 degrees Fahrenheit.
2. In a microwave safe bowl in 40 second intervals or in a small saucepan over medium heat, melt butter. Allow it to cool while making the crumbs.
3. Use a food processor (prefeered), strong blender, or Ziploc bag and meat tenderizer/wooden spoon to bring the Oreo cookies to fine crumbs. Ensure there are no large pieces of Oreo cookies. You want smooth, fine crumbs!
4. Mix butter and Oreo crumbs together.
5. In a 9 or 9.5 inch pie pan, pat the Oreo mixture on the bottom and around the sides of the pan. Smooth the crust as best as you can using your hands, the back of a spoon, or a glass!
6. Bake the crust at 350 for 10 minutes.
7. Allow the crust to cool.

For the Pie Filling

1. Over a medium saucepan, sift sugar, corn starch, unsweetened cocoa powder, and salt together. Whisk until combined.
2. In a medium bowl, whisk milk, heavy whipping cream, and egg yolks together.
3. Over medium heat, slowly add the milk mixture to the saucepan. Whisk consistently until mixture begins to boil. As soon as the mixture begins to boil, lower the temperature and cook for another minute until thick and smooth.
4. Immediately after removing the mixture from the heat, stir in unsalted butter, chopped chocolate, and vanilla extract.
5. Pour chocolate filling into the prepared crust. Place a piece of cling wrap on the surface of the pie and allow it to cool at room temperature for about 30 minutes before transferring to the fridge. Allow pie to chill for at least 6 hours.

For the Whipped Cream

1. After pie has chilled, prepare whipped cream by whipping heavy whipping cream and powdered sugar together on low speed in a medium-sized bowl.
2. Increase speed slowly as you mix. The mixture will become smooth and silky. A beater lifted from the whipped cream should create soft/medium peaks. Do not overbeat.
3. Spread or pipe the whipped cream over the chilled pie. Top with chocolate shavings, chocolate curls, chocolate chips, or any other desired topping!