Heat the 4 tablespoons unsalted butter over medium-high heat in a saucepan. Add in the 2 diced Granny Smith apples, 1 teaspoon cinnamon, and ¼ cup brown sugar. Cook the mixture until the apples are tender.
In a small bowl, mix the 1 teaspoon cornstarch and 1 tablespoon water, add it to the saucepan, and continue to cook until it thickens. Remove from heat.
Roll out the 2 refrigerated pie crusts and cut 4-inch circles from them. Place a tablespoon of apple filling in one half of each circle, leaving a ½-inch boarder.
Wet the edges of the circle, fold the dough in half over the pie filling, and seal the edges with a fork. Cut three slits into the top of the pies.
In a small bowl, whisk the 1 large egg and 1 tablespoon water together and brush the top of the hand pies. Place the hand pies into the basket of the air fryer. Cook at 350 degrees Fahrenheit for 8-10 minutes or until golden brown.
While the hand pies are cooking in a small bowl, mix the ½ cup powdered sugar and 2 tablespoons milk. Once the hand pies are finished, brush them with the glaze and sprinkle with coarse sugar.
Notes
You can also use your favorite pie filling inside of the hand pies.