Preheat the oven to 350°F (175°C) and prepare your pie dish.

Lay the pie crust in the dish, ensuring it fits snugly.

In a mixing bowl, whisk together the milk, sugar, eggs, cinnamon, and vanilla until smooth.

Pour the custard filling into the prepared crust.

Bake for 40-45 minutes until set but slightly jiggly in the center.

Allow to cool at room temperature before slicing. Serve with whipped cream or an extra sprinkle of cinnamon.