Preheat oven to 375°. Spray a 9 inch glass pie dish with cooking spray.

Crust: Set aside 1 tablespoon of the crumbs, then mix the remaining crumbs with the 2 tablespoons sugar, cinnamon, and salt. Add the butter and stir until mixed, then stir in the egg white. Press crumb mixture into bottom and up sides of pie dish and bake at 375° for about 8 minutes. Let cool.

Filling Whisk sugar, cornstarch, cocoa, salt, espresso, pepper, egg and yolk together in a bowl.

Place milk in a medium, heavy saucepan over medium-high heat; cook until milk reaches 180° or until tiny bubbles form around edge (do not boil). Gradually add hot milk to egg mixture, stirring constantly with a whisk. Return milk mixture to pan. Cook, stirring constantly, until mixture thickens (recipe say 10 minutes, but mine was thick in about 3 so I did 5). Remove from heat. Add chocolate and stir until melted, then stir in the vanilla.

Place the saucepan in a large bowl of ice water so that the ice water comes up around the sides. Whisk, then let stand for about 10 minutes, whisking often, to quick cool.

Pour filling into crust, and cover surface of filling with plastic wrap. Chill for 3 hours or until set; remove plastic wrap. Spread or pipe whipped topping over pie; sprinkle with reserved cracker crumbs.