In a large mixing bowl, combine flour, salt, and sugar. Add the cold, cubed butter and mix with your fingers or a pastry cutter until the mixture resembles coarse crumbs.

Gradually add ice water, one tablespoon at a time, until the dough comes together. Divide the dough into two discs, wrap in plastic wrap, and refrigerate for at least 30 minutes.

In another bowl, combine the diced apples, sugar, cinnamon, and lemon juice. Mix until the apples are well-coated. Set aside.

Preheat the oven to 375°F (190°C).

On a lightly floured surface, roll out one disc of dough to about ⅛ inch thick. Cut out circles using a 4-inch round cutter.

Place a tablespoon of the apple filling in the center of each circle. Fold the dough over to create a half-moon shape and seal the edges with your fingers or a fork. Repeat with the second disc of dough.

Place the hand pies on a baking sheet lined with parchment paper. Beat the egg and brush the tops of the pies with the egg wash. Sprinkle a little sugar on top for extra sweetness.

Bake in the preheated oven for 25 minutes or until golden brown.

Allow to cool slightly before serving.