Make the pie crust: Dissolve the sourdough discard in the water and set aside.
28 grams water, 42 grams sourdough discard
In a large mixing bowl, toss the butter, salt and all-purpose flour together making sure all the butter pieces are completely coated.
113 grams unsalted butter, 120 grams all-purpose flour, 6 grams salt
Use your fingers to squeeze the butter pieces into flat discs, and continue working the butter into the flour by rubbing everything together using your palms.
Make a well in the center of your flour mixture and pour the discard mixture in the center. Use a stiff spatula or sturdy wooden spoon to toss the flour and discard the mixture together.
Transfer any portions of dough that are starting to clump together on a piece of plastic wrap. Sprinkle a few drops of water on any dry portions of flour.
Use the piece of plastic wrap to bring the dough together until it forms a cohesive mass (it's ok if it appears a little dry).
Wrap the dough in plastic wrap and refrigerate it for at least 30 minutes.
Laminate the dough: Unwrap the dough and set it out on a lightly floured work surface. Use a rolling pin to flatten the dough out into a large rectangle about 8 by 10 inches, it doesn’t have to be exact.
Working with the longer side, fold the dough into thirds like you’re folding a letter.
Roll the dough into a long rectangle, about 6 by 18 inches, the size doesn’t have to be exact.
Working with the shorter sides, fold the dough in thirds once more. Wrap the dough in plastic wrap and chill for at least 1 hour.
Make the filling: Combine the diced apples, sugar, spices and salt in a small saucepan and stir.
250 grams Granny Smith Apples, ½ teaspoon ground cinnamon, ¼ teaspoon ground cloves, ¼ teaspoon grated nutmeg, ½ teaspoon ground ginger, 4 grams salt, 100 grams dark brown sugar
Cook the filling at medium heat until the juices are thickened and the apples are tender, about 10 minutes. Transfer the filling to a bowl, stir in the apple cider vinegar and let the filling cool completely.
8 grams apple cider vinegar
Roll out the dough: Transfer the dough out on a lightly floured work surface.
Using a rolling pin, flatten the dough into an 11 by 15-inch rectangle, it’s okay if the edges are a little scraggly.
Trim ½ an inch from the edges, until you have a 10 by 14-inch rectangle.
Divide the dough into 12 portions, about 2 ½ by 4 ½ inch rectangles.
Prep: Preheat the oven to 375 F with a rack in the middle. Line a large baking sheet with parchment paper.
Assemble the pies: Arrange 6 portions of dough on the prepared baking sheet.
Distribute the filling evenly among the 6 rectangles. Cover the filling with another portion of dough.
Using a fork, seal the edges of the dough. Brush the dough with egg wash and sprinkle Demarara sugar on top. Score the top of the dough using a lame or a sharp paring knife.
1 egg, 12 grams Demarara sugar
Bake: Bake the hand pies for 20 to 25 minutes or until golden brown. Transfer the baked pies to a cooling rack.
Enjoy and store: These pies are best enjoyed fresh from the oven. Store leftover pies in an airtight container in the refrigerator for up to 1 week. Refresh the pies in a 350 F oven for 10 to 15 minutes.