01 - Preheat oven to 350°F. Arrange the unbaked pie crust in a 9-inch pie pan and shape the edges as preferred.
02 - In a medium saucepan, combine whole milk and heavy cream. Heat over medium until just steaming, ensuring it does not boil. Remove from heat.
03 - In a mixing bowl, vigorously whisk eggs, granulated sugar, cornstarch, vanilla extract, ground cinnamon, and sea salt until fully incorporated and smooth.
04 - Gradually pour the warm milk-cream mixture into the egg mixture, whisking constantly to combine and prevent curdling.
05 - Pass the custard liquid through a fine-mesh sieve into a clean bowl to eliminate any lumps and ensure a smooth consistency.
06 - Pour the strained custard into the prepared pie crust, gently smoothing the surface if needed.
07 - Bake for 45-50 minutes until the center is set but still yields a slight wobble when moved. Shield crust edges with foil if they brown too rapidly.
08 - Transfer the baked pie to a wire rack and allow to cool completely. Custard will finish setting as it cools.
09 - Sprinkle the top with ground cinnamon. Optionally, dust lightly with powdered sugar before serving.
10 - Refrigerate pie for a minimum of 2 hours before slicing to achieve ideal texture.