Preheat the oven to 375°F (190°C). Roll out the pie crust and press it into a 9-inch pie dish. Line with parchment paper and fill with weights. Bake for 15 minutes, remove weights, and bake for another 5 minutes. Let cool.

In a saucepan, combine whole milk and heavy cream and heat gently over medium-low. Add ground cinnamon and vanilla extract. Stir until steaming; allow it to steep for 10 minutes.

In a mixing bowl, whisk the eggs with granulated sugar and a pinch of salt until pale and smooth, about 2-3 minutes.

Slowly pour the warm cream into the egg mixture while stirring continuously to temper the eggs. Strain the mixture back into the pan through a fine sieve.

Reduce the oven temperature to 325°F (162°C). Pour the custard into the pre-baked crust and bake for 35-40 minutes until set around the edges but jiggles in the center.

Let the pie cool at room temperature for 20-30 minutes, then refrigerate for at least 2 hours or overnight before serving.