For the crust:

1. Whisk the flour, sugar and salt together in a medium bowl. Cut in the cold butter until the mixture resembles coarse, pea-sized crumbs. Add ice cold water, and gently knead the dough a few times in the bowl until it all comes together.
2. Divide in 2 equal parts, flatten each ball into a thick disk, and wrap them separately in plastic wrap. Refrigerate for 30 minutes to 1 hour.

Filling and assembling:

1. Melt the butter in a large skillet over medium heat. Add diced apples, and cook for about 5-8 minutes, stirring often, until apples are soft and tender. Mix in white and brown sugar, cinnamon, nutmeg, all spice, and a pinch of salt. Pour in the lemon juice, and continue cooking for about 2 minutes, until apples are soft and sticky. Add the flour, mix well, and allow mixture to thicken. Remove from heat and let cool at room temperature for 30 minutes.
2. Preheat the oven to 375°F (190°C) and line a large baking sheet with parchment paper.
3. On a lightly floured work surface, roll out the first chilled dough. Using a 3.5-inch/9cm cookie cutter**, cut into 12 circles (these are the bottom crusts). Re-roll any scraps as needed, and transfer to the baking sheet. Repeat with the second pie dough, and cut slits into each of the remaining 12 circles, using a small knife, so that steam can escape while baking***.
4. Divide the apple filling into the 12 bottom circles (no slits), leaving a border all around. Gently brush the edge with water, then cover with the remaining 12 circles (with a slit). Press your fingers all around the edges to seal, then crimp with a fork. Lightly brush the top with egg wash, and sprinkle with coarse sugar. Refrigerate for 15 minutes.
5. Bake for 25 minutes or until hand pies are golden brown, rotating the pan halfway through baking. Remove from the oven and let cool for about 10 minutes before serving.