Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.

In a medium bowl, combine diced apples, brown sugar, ground cinnamon, nutmeg, allspice, ground ginger, and salt. Add unsalted butter and vanilla, mixing until well-coated. Stir in cornstarch slurry.

In a small bowl, whisk together beaten egg and milk (or plant-based milk) to create the egg wash.

Roll out pie dough, cut into circles, spoon apple filling into center, brush with egg wash, and sprinkle with coarse brown sugar.

Place assembled pies on the prepared baking sheet and bake for 20-25 minutes until golden brown.

Let cool on wire rack for 10 minutes before serving.