Preheat oven to 325F and place pie crust onto a baking sheet. Prick bottom of crust with a fork or use pie weights (dried beans are good)
Bake for 10-12 minutes to partially cook and set aside.
Mix cornstarch and sugar in a small bowl until combined.
In a medium saucepan over medium heat, add the cornstarch mixture, melted butter, and heavy whipping cream to a boil, stirring constantly until thickened.
Add vanilla and stir. Pour hot cream into prepared pie crust and smooth the top.
Top with melted butter and evenly sprinkle with desired amount of cinnamon sugar.
Bake for 25 minutes and broil for about 1 minute.
Cool until room temperature and place in the fridge to set for a least 1 hour.
Serve or store covered in the refrigerator.