Strawberry and Blueberry Hand Pies

Make the Pie Crust
1 Shred the unsalted butter using a cheese grater. Place on a plate, cover with plastic wrap, and transfer to the freezer until time to use.
2 Combine the milk with the apple cider vinegar in a liquid measuring cup. Refrigerate until ready to use.
3 In a large bowl, whisk together the flour with the sugar, cornstarch and salt until incorporated. 
4 Remove the shredded, frozen butter from the freezer and add it to the flour mixture. Stir gently until the ingredients are well-combined, and the butter appears to be the size of peas and the texture of wet sand.
5 Drizzle half of the milk mixture over the dry ingredients. Using a plastic spatula, lightly mix the flour with the liquid. Repeat the process by drizzling a bit more in, repeating until the dough holds together when pressed against the side of the bowl. (You should still be able to see chunks of butter in it.) If necessary, add additional cold milk, 1 tablespoon at a time, until you find the desired consistency.
6 Form the dough into a disk, wrap tightly in plastic wrap and refrigerate for at least 1 hour. 
Make the Filling
1 When the dough is done refrigerating, measure out the chopped strawberries and blueberries in a medium-sized bowl.
2 Add the raw sugar and cornstarch. Toss until combined, then set aside.
Make the Hand Pies
1 Preheat the oven to 350°F. Line a large baking sheet with parchment paper or a nonstick baking mat. Set aside.
2 Lightly flour a clean, flat surface, and roll out the pie crust. Using a 4 1/2" to 5" round cookie cutter, cut rounds into the dough for the individual pies.
3 Transfer the dough rounds to the prepared baking sheet, then measure out about 2 tablespoons of the filling into them. 
4 Brush egg around the edges of half the round, then seal with your fingers or a fork. 
5 Repeat the process until all 10 pies have been made.
6 Brush the tops of the hand pies with the egg, then gently cut two vents in the top of each.
7 Transfer the baking sheet to the oven, and bake for 35-45 minutes, or until the tops are golden brown. (Please note that my oven is crazy old, and if you have a new oven, you need to check on your hand pies when they reach the 20 minute mark to confirm you don't burn them.)
8 When cooled, remove from the oven, and let cool for 5 minutes before devouring!