Preheat oven to 350 °F (175 °C). Grease a 9-inch pie dish.

In a bowl, mix chocolate wafer crumbs and melted butter until combined. Press mixture into bottom and up the sides of the pie dish to form a crust.

In a separate bowl, whisk together sugar, cocoa powder, flour, and salt.

Whisk in eggs until smooth, then gradually whisk in milk, cream, chopped chocolate, and vanilla extract until well combined.

Pour filling into the prepared crust.

Bake for 35–40 minutes, or until the edges are set and the center is slightly jiggly—a toothpick inserted in the center should come out mostly clean with a few moist crumbs.

Let the pie rest for at least 10 minutes; the center will finish baking from residual heat while setting.

Serve warm, optionally topped with vanilla ice cream, whipped cream, or fresh berries.