01 - Preheat oven to 350°F. Arrange unbaked 9-inch pie crust in pie pan, crimp or trim edges as desired.
02 - In medium saucepan, combine whole milk and heavy cream. Heat gently over medium heat until steaming, without boiling. Remove from heat.
03 - In mixing bowl, whisk eggs, granulated sugar, cornstarch, vanilla extract, ground cinnamon, and sea salt until mixture is smooth.
04 - Gradually pour warm dairy mixture into egg mixture while whisking constantly to prevent curdling.
05 - Pass custard through a fine-mesh sieve into a clean bowl to achieve a silky consistency.
06 - Pour strained custard filling evenly into prepared pie crust.
07 - Bake at 350°F for 45 to 50 minutes, or until the center is set but slightly wobbly. Shield crust edges with foil if browning too quickly.
08 - Transfer pie to wire rack and allow to cool. Custard will firm as it cools.
09 - Sprinkle surface with ground cinnamon; dust with powdered sugar if desired before serving.
10 - Refrigerate pie for a minimum of 2 hours prior to slicing and serving.