Preheat oven to 400°. Pour apple cider, vanilla, and lemon juice into the unbaked pie crust without mixing.
In a bowl combine sugar and flour. Sprinkle over juice in pie crust. Do not mix.
Cut butter into chunks and float on top. Sprinkle with cinnamon.
Bake at 400° for 40 minutes.
Reduce temperature to 375° and bake for another 30-35 minutes or until thickened.
Chill for 3+ hours or until fully set (preferably overnight).
