Make the crust: Preheat oven to 350°F (175°C). Crush the cookies into fine crumbs using a food processor or by hand. Mix with melted butter until evenly combined. Press into the bottom and sides of a 9-inch pie dish. Bake for 8–10 minutes. Let cool completely.

Make the filling: In a saucepan, whisk together granulated sugar, brown sugar, cornstarch, and salt. Gradually whisk in the milk and heavy cream until smooth.

Place over medium heat, whisking constantly, until the mixture thickens and begins to bubble. Reduce heat to low and cook for 2 more minutes.

Slowly whisk about 1 cup of the hot mixture into the beaten egg yolks to temper them, then return the mixture to the saucepan. Cook over medium heat for another 2 minutes, stirring constantly.

Remove from heat and stir in the butter until smooth. Pour the filling into the cooled crust. Cover with plastic wrap directly on the surface and chill for at least 4 hours or overnight.

Make the topping: Whip cold heavy cream with powdered sugar and vanilla until stiff peaks form. Spread over the chilled pie. Garnish with crushed cookies if desired.