Prepare the pie crust by placing it in a 9-inch pie pan. If making your own, roll out the dough and fit it into the pan.

In a medium saucepan, combine whole milk and heavy cream. Heat over medium heat until warm but not boiling.

In a large mixing bowl, whisk together granulated sugar, eggs, vanilla extract, ground cinnamon, and salt until well combined.

Slowly pour the warm milk and cream mixture into the egg mixture while whisking continuously to prevent scrambling.

Pour the custard mixture into the prepared pie crust and bake in a preheated oven at 350°F for 45-50 minutes until set.

Let the pie cool at room temperature for 60 minutes, then refrigerate for at least 120 minutes before serving.