FOR CRUST; Blend flour and sugar, cut in butter into small pieces and work into flour mixture by hand or fork, (DON'T Over Mix); then add egg yolk, stir gently until well incorporated into the flour-butter mixture.
Gently form two balls of dough; ONE LARGER, for the bottom crust; the other ball is for the top; WRAP dough in wax paper and set in refrigerator for 1 hour.
Line pizza pan with parchment paper; crumble large ball of dough on to the parchment paper and press to fit lined pan.
Then roll small dough ball in between waxed paper, press or roll dough to 1/8 inch thick, cut into strips to layer over apple filling (cut any sze it doesn't matter, have fun); NOTE use kitcken knife to lift strips onto the apple filling in a crisscross pattern, (if strips break, DO NOT WORRY, arrange into pattern of squares).
FOR FILLING: place apples in medium saucepan with water (or cider), and slowly warm slowly, then add flour, sugar, cinnamon, nutmeg and butter to apple mixture; cook over medium-high heat,stirring often until thick; set aside and cool.
Pour filling over bottom crust, spread evenly, then layer top with strips of dough; Bake at 375 degrees for 35-40 minutes, until browned.