Preheat your oven to 375°F (190°C). Fit your pie crust into a 9-inch pie dish, pressing it against the sides and bottom. Line it with parchment paper, then fill with pie weights or dried beans. Blind-bake for 15 minutes, then carefully remove the weights and bake for an additional 5 minutes or until the crust is golden and fragrant.

In a medium saucepan over medium heat, combine whole milk, heavy cream, ground cinnamon, and vanilla extract. Stir gently, heating until steamy but not boiling—this should take about 5 minutes.

In a mixing bowl, whisk together the room-temperature eggs and granulated sugar until pale and slightly frothy, about 3-4 minutes.

Slowly pour the heated milk mixture into the egg mixture while whisking continuously to prevent curdling. Optionally, strain the custard mixture through a fine mesh sieve.

Lower the oven temperature to 325°F (160°C). Carefully pour the custard mixture into your pre-baked crust and bake for 35-40 minutes, or until the edges are set and the center has a slight jiggle.

Remove the pie from the oven and let it cool at room temperature for about 30 minutes. Then refrigerate for at least 2 hours to allow it to fully set.