Begin by preheating your oven. Thaw the unbaked pie crust and roll it onto a 9-inch pie pan.

Next, follow the instructions on the pie crust packaging and bake until golden brown. Once done, set it aside while you prepare the pie filling.

In a small bowl, lightly beat your egg yolks and keep them aside.

Then, in a medium saucepan over medium-high heat, mix brown sugar, flour, cornstarch, salt, and cinnamon with two cups of whole milk.

Whisk everything together and cook until thickened. This may take up to 10-15 minutes depending on the heat level, so ensure that it is thick before moving to the next step.

Then, add a spoonful of the hot mixture to the egg yolks to temper them. Gradually whisk in the egg yolks to the saucepan and stir well.

Melt the butter, add vanilla extract, and continue cooking for another 5 minutes while stirring gently until its thick enough.

To make the pie, slowly pour the filling into a prepared pan and allow the pie to cool for at least 30 minutes. Once cooled, cover with plastic wrap and place in the fridge for at least 2 hours or overnight until you're ready to serve.

Before serving, add a dollop of whipped cream and a sprinkle of cinnamon to the pie for garnish.