For crust:
5 Tbs. butter, melted
1-1/2 cups (cinnamon) graham cracker crumbs (about twelve 5 by 2-1/2 inch crackers)
2 tbs. sugar
1/2 tsp. salt
for filling:
6 ounces bittersweet chocolate (not more than 60%)
2 tbsp. corn starch
1/3 cup packed brown sugar, divided
2 whole eggs
2 egg yolks
2 cups whole milk
1/2 cup heavy cream
1/2 tsp. salt
1/2 stick (1/4 cup) butter, cut into cubes
1 tsp pure vanilla extract
for whipped cream:
1-1/2 cups heavy cream
5 tbs. confectioner’s sugar
1/2 tsp. cinnamon
make crust: preheat oven to 350º with rack in the middle. stir together all crust ingredients. press over bottom and up the sides of a 9-inch pie dish. bake until set, 12-15 minutes.
make filling: melt chocolate in a large bowl. set aside. stir together cornstarch and 2 tbs. of brown sugar in a small bowl. whisk together the eggs and the yolks and combine with cornstarch and sugar mixture. stir together milk, cream, salt, and remaining sugar in a heavy bottomed, medium pot. bring to just a boil. slowly whisk in half of milk mixture into half of egg mixture. Whisk this mixture back into the remaining milk mixture and bring to a boil, whisking constantly. Off the heat, stir in the butter and vanilla. Strain through a fine-mesh sieve into the melted chocolate. Whisk to combine thoroughly. Pour into cooled pie crust. Cover the surface with parchment or plastic wrap and chill until set, about 3 hours.
In the meantime, you can whip up the whipped cream ingredients in a cold mixing bowl.
Crust can be baked up to two days in advance and the pie can be chilled, loosely covered, for up to one day.