1 1/4 cups all-purpose flour
1/4 tsp salt
1/2 cup solid vegetable shortening, cold
3 tbsp ice water
2 tbsp cinnamon
2 tbsp cornstarch
1/3 cup packed light brown sugar, divided
2 whole large eggs
2 large egg yolks
2 cups whole milk
1/2 cup heavy cream
1/8 tsp salt
1/2 stick unsalted butter, cut into tablespoons
1 tsp pure vanilla extract
5 tbsp confectioners sugar
1/2 tsp cinnamonDIRECTIONS
Melt chocolate in a large bowl. Stir together cornstarch and 2 tablespoons brown sugar in a small bowl.
Whisk together whole eggs and yolks in another bowl, then whisk in cornstarch mixture.
Stir together milk, cream, salt, and remaining brown sugar in a heavy medium saucepan and bring just to a boil over medium heat. Pour half of milk mixture into egg mixture in a slow stream, whisking, then pour egg mixture into remaining milk mixture. Bring to a boil over medium-low heat, whisking constantly, then boil, whisking, 1 minute. Remove from heat and whisk in butter and vanilla. Strain through a fine-mesh sieve into melted chocolate and whisk to combine.
Transfer hot filling to crust and chill, its surface covered with parchment, until filling is cold, about 3 hours.