Preheat your oven to 375°F (190°C). Roll out your pie crust and line a 9-inch pie dish, covering it with parchment paper and weights. Blind-bake for 15 minutes, then remove weights and bake for an additional 5 minutes until golden.

In a medium saucepan, combine 1½ cups of whole milk and 1 cup of heavy cream. Add 1½ teaspoons of ground cinnamon and 2 teaspoons of vanilla, heating until steaming but not boiling.

In a mixing bowl, crack 4 eggs and whisk with ¾ cup of sugar and a pinch of salt until pale and smooth, about 2-3 minutes.

Gradually add the hot milk mixture to the eggs while continuously whisking to prevent curdling. Strain the mixture through a fine-mesh sieve into a clean bowl.

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

Remove from the oven and allow to cool at room temperature for about an hour. Refrigerate for at least 2 hours before serving.