First, make the crust. In the bowl of a stand mixer, combine the flour, sugar and salt. Using a pastry blender, two knives, or your fingers, mix in the butter, until mixture becomes crumbly. Using the dough hook of the stand mixer, mix in the water until a dough forms. Turn dough out onto a lightly floured surface and form into a disk. Wrap in saran wrap and place in refrigerator while you prepare the apples.
Next, hollow out six of the apples. Use an apple corer to get it started, but be sure not to go all the way down to the bottom. After you’ve gotten it started with the apple corer, move to using your paring knife. You want to scoop out enough to make a little bowl in the middle of the apple that you can put the filling in. Discard the core and seeds, but save any other apple scraps for the filling. Place the apples in a small baking pan lined with aluminum foil.
Now it’s time to make the filling. Chop up the one remaining apple and add it to the other apple scraps you’ve saved. In a small saute pan, cook the chopped apples, toasted walnuts, maple syrup, butter, brown sugar, lemon juice, cinnamon and cloves over medium heat for 5-10 minutes, until the sauce becomes syrupy. Turn off heat and scoop a heaping tablespoon (or more, if your apples are larger) into each of the hollowed out apples. If you have extra filling, save it to make little hand pies.
Preheat oven to 390 degrees Fahrenheit.
Remove the pie dough from the refrigerator and roll it out to ¼-inch thickness on a lightly floured surface. Using an 8-inch culinary ring (or round cookie cutter), cut out circles of dough to place on top of the apples. Cut two little slits in the top of each circle to allow for venting while baking. Mold each disk gently on top of the apples.
If you have extra dough and filling, make hand pies. Simply use two of the dough disks, and scoop two teaspoons or so of filling in between, pinching the two disks together to form a seal. Use the tines of a fork to further crimp the edges and ensure that none of the filling leaks out during baking. Place these hand pies in a separate baking dish lined with aluminum foil.
In a small bowl, gently beat the egg to make the egg wash. Brush this over the tops of the apples and onto the hand pies (if making.)
Place both baking dishes in the oven and bake at 390 degrees for 25 minutes. Serve warm with vanilla ice cream or Greek yogurt.