Preheat your oven to 375°F (190°C). Roll out your pie crust and fit it into a 9-inch pie dish. Cover with parchment paper and fill with weights or beans. Blind-bake for 15 minutes, then remove weights and bake for an additional 5 minutes.

In a medium saucepan, combine whole milk, heavy cream, ground cinnamon, and pure vanilla extract. Heat over medium-low until steaming, but do not boil. Cool slightly.

In a large bowl, whisk together the eggs, granulated sugar, and salt until smooth and pale, about 2-3 minutes.

Slowly pour the warm cream mixture into the egg mixture while whisking continuously. Strain through a fine mesh sieve into a clean bowl.

Pour the custard mixture into the pre-baked pie crust. Bake at 325°F (160°C) for 35-40 minutes until edges are set and center is jiggly.

Let the pie cool at room temperature for 1-2 hours, then refrigerate for at least 2 hours before slicing.