To make the dough, combine the flour, baking powder, and salt in a large bowl.

Cut the cubes of butter into the dry ingredients using two forks or a pastry cutter, until the mixture resembles small peas (you can also use a food processor or a stand mixer fitted with the paddle attachment).

Add vinegar and ice water and gently form dough into a ball.

This step is optional, but it creates a flakier crust: Place dough on the counter. Taking a small piece of dough at a time, push the dough across the counter using the heel of your hand. Scrape up the dough using your hands (a metal dough scraper also works well here) and gently form all of the scraps into a new ball.

Divide dough into two balls and wrap in plastic wrap or a plastic bag and refrigerate for at least 1 hour (or up to 2 days).

Meanwhile, make the filling. Combine the peaches and sugar in a bowl and let sit for an hour (you can do this while your dough is chilling).

Drain the juices from the peaches and sugar. Add the cinnamon, cornstarch, peach preserves, and lemon juice and stir to combine.

Preheat oven to 375 degrees F. Line 2 baking sheets with parchment paper. Beat egg and water together in a small bowl and set aside.

Remove dough from the fridge. Roll each portion out on a flat, lightly floured surface (a little thicker than a tortilla).

Using a circle cutter, large cup, or plastic top that is about 5 inches in diameter, cut the dough into circles (you should have enough for 4 circles with each ball of dough).

Gently transfer the circles to your prepared baking sheets.

Spoon 1 tablespoon of filling in the center of each dough circle, making sure not to get too much of the juices. Brush one half of the outer edge of each circle with the egg wash, and fold each circle in half making a semi-circle. Press edges together and crimp with the tines of a fork.

Brush egg wash over the top of each pie and sprinkle with coarse sugar. Bake for 20-30 minutes, or until golden brown.

Remove from oven and let cool slightly. Serve with vanilla ice cream or whipped cream and enjoy!