In a large mixing bowl, combine all-purpose flour, salt, and granulated sugar. Cut in cold unsalted butter until the mixture resembles coarse crumbs.

Gradually mix in ice water until the dough begins to hold together. Wrap the dough in plastic wrap and refrigerate for 30 minutes.

Peel, core, and dice the medium apples. Toss with granulated sugar, cinnamon, and lemon juice until well-coated.

Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

On a lightly floured surface, roll the chilled dough to about 1/8 inch thick. Cut out 4-5 inch circles.

Place a generous spoonful of apple filling onto the center of each dough circle, leaving space at the edges.

Fold each circle in half, press edges together to seal, and crimp with a fork.

Brush the tops with egg wash and sprinkle with additional sugar if desired.

Bake on the prepared baking sheet for 30-35 minutes until golden brown and flaky.

Remove from oven and let cool on a wire rack for at least 20 minutes before serving.