Preheat your oven to 375°F (190°C). Roll out the pie crust and fit it into a 9-inch pie dish. Line the crust with parchment paper and fill it with pie weights or dried beans. Bake for 15 minutes, remove the weights and parchment, and bake for an additional 5 minutes until golden. Set aside to cool slightly.

In a medium saucepan, combine the whole milk and heavy cream over medium heat. Add ground cinnamon and vanilla extract, stirring occasionally until steaming but not boiling. If using a cinnamon stick, steep it in the warm mixture.

In a large mixing bowl, whisk together fresh eggs, granulated sugar, and salt until the mixture is pale and slightly frothy. Use a handheld whisk or electric mixer for ease.

Slowly pour the warm milk mixture into the egg mixture while continuously whisking to avoid curdling the eggs. After fully incorporating, strain the custard through a fine-mesh sieve into another bowl, discarding any solids.

Lower the oven temperature to 325°F (160°C). Carefully pour the prepared custard into the pre-baked pie crust, taking care not to overfill. Bake for 35–40 minutes, until the edges are set and the center jiggles slightly.

Remove the pie from the oven and let it cool on a wire rack at room temperature for about an hour. Once cooled, refrigerate for at least 2 hours to allow the custard to firm up.