Preheat oven to 400° F. Plave the pie shell in a pie plate. Line the thinly sliced apples around the pie shell. Place them close together but not on top of one another.
Beat the sugar, cinnamon, skim milk, and vanilla together until there are no lumps. Take 4 Tablespoons of the milk mixture and stir into the combined flour and cornstarch to make a paste.
Stir the paste back into the milk mixture. Pour this mixture over the apples. Bake in preheated oven for 45-50 minutes. Serve warm or cold. ServesServings: 6