Preheat the oven to 375°F.
Lightly grease a 9-inch pie pan with cooking spray.
Roll out the refrigerated pie crust according to package directions.
Place the pie crust into the prepared pie pan, pressing it gently against the bottom and sides.
Trim any excess crust from the edges, if necessary.
Shape the edge of the crust as desired by crimping, pinching, or pressing with a fork.
Set the prepared pie crust aside.
In a medium mixing bowl, add the eggs, granulated sugar, cornstarch, ground cinnamon, and apple butter.
Beat the mixture until fully combined and smooth.
Add the milk to the apple butter mixture.
Whisk until the filling is evenly blended and pourable.
Pour the filling into the unbaked pie crust.
Use a spoon to gently distribute the filling evenly, if needed.
Place the pie pan in the preheated oven.
Bake for 60 to 65 minutes, or until the center is set.
The center may remain slightly jiggly, but a knife inserted near the center should come out nearly clean.
If the crust edges brown too quickly, cover them loosely with foil or a pie shield.
Remove the pie from the oven.
Transfer the pie to a wire rack and allow it to cool before slicing.
Once cooled, slice the pie into 8 servings.
Top each slice with whipped cream and a light sprinkle of ground cinnamon, if desired.
Serve slightly warm, at room temperature, or chilled.
Store any leftovers in the refrigerator.