In a medium saucepan over low to medium heat, bring water, cornstarch, sugar, cinnamon, and lemon juice to a boil.
Continue cooking for 3 minutes or until sauce thickens, stirring constantly.
Add apples, stir and let simmer for 8-10 minutes.
Remove from heat, let cool completely.
Unroll pie crusts on a lightly floured surface and cut pie dough into 5” circles.
Using your finger, wet the edges of each pie dough before filling, to help seal the dough.
Add a heaping tablespoon of the apple filling to the center of each piece of dough.
Fold dough in half and using a fork, crimp the edges to help secure the filling.
Place hand pies on the prepared baking sheet.
In a small bowl, whisk egg and water together and brush the top of each hand pie with the egg wash.
Bake at 400° for approximately 15-18 minutes or until golden brown.
Remove from oven and serve warm.