Step 1: Preheat the Oven

1. Preheat your oven to 350°F (175°C).
2. Place the pie crust in a 9-inch pie pan, crimping the edges as desired. Set aside.

Step 2: Melt the Chocolate and Butter

1. In a medium saucepan, melt the dark chocolate and butter over low heat, stirring frequently.
2. Once melted, remove from heat and let cool slightly.

Step 3: Prepare the Filling

1. In a mixing bowl, whisk together the sugar, cocoa powder, and salt until combined.
2. Add the eggs one at a time, whisking well after each addition.
3. Stir in the milk, vanilla extract, and the melted chocolate mixture. Mix until smooth.

Step 4: Assemble the Pie

1. Pour the chocolate filling into the prepared pie crust, spreading it evenly.
2. Place the pie pan on a baking sheet to catch any drips.

Step 5: Bake the Pie

1. Bake for 35-40 minutes, or until the filling is set but still slightly jiggly in the center.
2. Remove from the oven and let cool on a wire rack.

Step 6: Chill and Serve

1. For best results, chill the pie in the refrigerator for at least 2 hours before serving.
2. Serve with a dollop of whipped cream or a sprinkle of powdered sugar, if desired.