Preheat your oven to 375°F (190°C). Fit the pie crust into a 9-inch pie dish, line with parchment paper, fill with weights, and bake for 15 minutes. Remove weights and bake for another 5 minutes until golden.

In a saucepan, combine whole milk and heavy cream with ground cinnamon and vanilla. Heat over medium until steaming, not boiling, allowing flavors to meld.

In a bowl, whisk together eggs, granulated sugar, and salt until pale and frothy.

Slowly pour the warm milk mixture into the egg mixture while whisking constantly to temper the eggs, then strain the mixture to ensure smoothness.

Pour the custard filling into the pre-baked crust. Reduce oven temperature to 325°F (160°C) and bake for 35-40 minutes until the edges are set and the center jiggles slightly.

Allow the pie to cool at room temperature for about an hour, then refrigerate for at least 2 hours before serving.