In a bowl, mix flour and salt. Cut butter into flour mixture until resembles coarse crumbs. Press crumb mixture on bottom and up sides of a 9" or 10" pie plate. Arrange apples over crust. Combine sugar and cinnamon and spread over apples. Bake at 375º for 20 minutes.

For custard, whisk evaporated milk with the egg and sugar until mixture is smooth. Pour over apples (after baking the initial 20 minutes). Bake an additional 45 minutes or longer till knife inserted near center of pie comes out clean. Cool on wire rack. Refrigerate leftovers.