Wash, dry, peel, core, and cubed your apples.
Add apples to a bowl and coat with cinnamon, sugar, nutmeg, and flour.
Remove apples from the bowl, and place apples into a large skillet with butter, and cook over medium heat until apples are tender; about 5 minutes.
Meanwhile, preheat the over to 400°F degrees, and coat the muffin pan with nonstick spray or additional melted butter.
Roll out dough and cut out 4" circles which will be inserted into each muffin tin. This will be the crust layer. You will have to re-roll the dough to make all 10 pie crust circles, however you should have enough left over dough to make little 1/4" lattice strips.
Once apples are tender, allow them to cool for 5 minutes before filling each pie crust cup.
Once each mini pie is filled, using a pastry dough cutter, form lattices in a crisscross patterns over each pie.
In a small bowl whisk the medium egg and water to create a light and fluffy egg wash. Once pies are assembled, brush them with the egg wash.
Bake for 20-25 minutes or until pies are golden brown and crust feels firm.
Allow Mini Apple Pies to fully cool before removing. Enjoy!