Step 1: Prepare the Oreo Cookie Crust : Preheat oven to 350°F (175°C). Combine crushed Oreo cookies and melted butter in a bowl. Press mixture evenly into a 9-inch pie pan. Bake for 8–10 minutes, then let cool completely.

Step 2: Make the Chocolate Filling : In a medium saucepan, whisk together sugar, cornstarch, and salt. Gradually add milk and heavy cream, whisking until smooth. Cook over medium heat, stirring constantly, until mixture begins to thicken and bubble. In a small bowl, lightly beat egg yolks. Slowly whisk about ½ cup hot mixture into yolks, then return mixture to saucepan. Cook for 2 more minutes, stirring constantly. Remove from heat. Stir in chopped chocolate, butter, and vanilla extract until smooth. Pour filling into cooled Oreo crust and smooth the top.

Step 3: Chill the Pie : Cover pie with plastic wrap and refrigerate for at least 3–4 hours, or until fully set.

Step 4: Prepare the Whipped Cream Topping : In a chilled bowl, beat heavy cream, powdered sugar, and vanilla extract until soft peaks form.Spread or pipe whipped cream over the chilled pie. Garnish with chocolate shavings or a dusting of cocoa powder.