In a bowl, whisk flour and salt. Using 2 forks/knives, cut butter into the dry ingredients until the pieces are pea sized. Gradually add water until the dough comes together. Shape into 5 equal sized balls, flatten to discs, and wrap separately in cling film. Rest in the refrigerator for half an hour. Preheat the oven to 425°F. In a large bowl toss together apples with sugars, our, cinnamon, nutmeg, and a pinch of salt. On a floured work surface, rollout each dough-round to approximately 8”. Spoon lling inside leaving 1 inch of dough empty around the perimeter. Fold dough over to enclose and secure the filling. Dot the exposed filling of each pie with butter. Place pies carefully on 1 or 2 parchment-lined baking sheets. Brush the pastry with milk. Bake for 35 minutes, until browned and crisp.