Preheat the oven to 175 degrees celsius.
Peel, core, and cut the apples into 5mm thick slices. In a large mixing bowl, combine in sugar, flour, cinnamon, nutmeg, and salt. Place the apple slices in the bowl and coat with lemon juice. With your hands, toss the apples around in the mixture and let stand for 15 minutes, stirring occasionally to coat the apples.
Grease four small 12cm diameter pie dishes. Cut out the bases from two shortcrust pastry sheets and place in each pie dish.
Pour the apple filling into the pie crust, and dot the top with the small pieces of butter.
Place the upper crust on top, trim, wave the edges with your fingers, and cut three small slits in the top. Alternatively, use a cookie cutter and cut out shapes from the second pastry sheet. Lay these on top in a pattern.
Lightly brush the top crust and edges with milk and sprinkle the top with sugar.
Slip a baking sheet under the pie and bake for 25 minutes. Reduce the temperature to 160 degrees, and continue baking for another 20 minutes. Let the pies cool for about 30 minutes before serving. One pie cut in half will feed two people.