• Preheat oven to 375°F (190°C).

Crust:

• Melt butter in a medium saucepan set over medium-low heat.
  1/3 cup (75ml) unsalted butter
• Remove from heat; stir in crumbs. Turn into a 9-inch (23 cm) shallow glass pie plate. Press evenly up sides and on bottom of pie plate.
  1 & 1/2 cups (375ml) chocolate cookie or graham wafer crumbs
• Bake for 8 min in centre of preheated oven until set.

Filling:

• In a medium saucepan, whisk cocoa with sugar, cornstarch and salt.
  1/4 cup (60ml) unsweetened cocoa powder, 1/4 cup (60ml) granulated sugar, 1/4 cup (60ml) cornstarch, 1/4 tsp salt
• Whisk in egg as best as you can; add milk. Continue to whisk until smooth and no lumps remain.
  1 egg, 2 & 1/2 cups (625ml) milk
• Set over medium heat. Stirring continuously, bring to a boil, about 3 to 5 min. Filling will thicken and bubble.
• Reduce heat to low; simmer gently and stir for 1 min. Add chocolate and butter. Stir until melted. Stir in vanilla.
  3/4 cup (175ml/90g) finely chopped bittersweet or semisweet chocolate, 2 Tbsp (30ml) unsalted butter, 1 Tbsp vanilla extract
• Turn into slightly cooled pie shell. Refrigerate for 2 hours or until cold and set.

Topping:

• Beat cream with sugar and vanilla until stiff peaks form. Spoon onto chilled pie. Swirl.
  1 & 1/2 cups (375ml) 35% cream, 2 Tbsp (30ml) granulated sugar, 1 tsp vanilla extract
• Grate chocolate over top if using. Refrigerate until ready to eat. Best eaten within a day of making.