First Step: Prepare the Crust Preheat your oven to 350°F (175–180°C). Process the chocolate sandwich cookies into fine crumbs. Mix these crumbs with melted unsalted butter until the texture resembles wet sand.

Press this mixture firmly into a 9-inch pie dish, ensuring it goes evenly up the sides. Bake for 10–12 minutes until the crust is set. To achieve a crispier crust, gently press down if the crust puffs slightly after baking. Let cool completely before filling.

Second Step: Make the Custard Filling In a medium saucepan, combine the granulated sugar, cornstarch, a pinch of salt, whole milk, heavy cream (if using), and egg yolks. Whisk thoroughly to avoid lumps.

Cook over medium heat, whisking constantly until the mixture thickens and just begins to gently boil this should take around 45 seconds after thickening.

Be careful to temper the egg yolks by slowly adding some of the hot milk mixture into them before combining fully to prevent curdling.

Third Step: Add Chocolate and Flavor Remove the pan from heat and quickly stir in the unsalted butter, chopped chocolate, and vanilla extract. Mix until smooth and glossy, ensuring the chocolate is fully melted.

Fourth Step: Fill the Pie Crust Pour the chocolate custard into the cooled chocolate cookie crust. Smooth out the top with a spatula.

To prevent a skin from forming on the custard, cover the surface directly with a piece of parchment or baking paper. Let the pie cool at room temperature for about 2 hours, then refrigerate for at least 4–6 hours or overnight for best firmness.

Final Step: Prepare and Add Whipped Cream Topping Just before serving, whip the heavy cream with sugar and vanilla extract until soft peaks form. Spread the whipped cream gently over the chilled custard.

Garnish with chocolate curls or grated chocolate for a polished finish. Serve chilled and enjoy the luscious textures and deep chocolate flavors.